here’s a bit more explanation, courtesy of Expert Village:

So what are the benefits of the LATCH system?  They are two-fold:

Ease of Installation

The LATCH system removes the need for using the seatbelt in the installation of a car seat.  Before LATCH, the most common installation method was to run the seat belt through a narrow hole on the back of the seat.  If you’ve never dealt with this first-hand, I’m sure you can still imagine the absolute pain this is to install, especially if you’re in a hurry to get somewhere and you need to bring your infant with you.  The new method of installation is simply to latch two anchor points from your car seat onto the hooks that are not coming standard in vehicles.  Generally, this simply requires pushing two pieces of metal together until you hear a “click.”

Increased Child Safety

Although convenience and ease of use are the main points behind the LATCH system, these aren’t the only considerations when a new system like this is adopted.  One huge problem with the old system that use seatbelts was that it was possible for the child to reach over and unclasp the belt.  Of course, this compromises the safety of the entire car seat and makes it very dangerous to drive with a child.  The anchor hooks used in the latch system do away with this danger for good:  The anchor points are impossible for a child to compromise in any way provided they are correctly installed and used.  So even though convenience is the main goal of LATCH, it’s hard to argue with the fact that a car seat that is easier to install means there are fewer ways to make a mistake in using it; this applies to any kind of childcare product whether we are talking about baby walkers or car seats!  Fewer possibilities for misuse definitely equate to more safety and peace of mind, and even cheap car seats will have adopted this system so the price doesn’t increase.  Definitely great news for those of us wanting to stretch our dollar a little further!

First of all, you must be sure that your infant has proper head support during your trip. You can find cheap car seats with head bolsters and/or inserts that will give the proper support to smaller babies.  Advances are constantly being made in the world of infant car seats, so be sure to check out the latest product availability to ensure that you are providing the best possible experience for your child.

Also, be sure to correctly put the harness straps in the provided slots.  Generally, you want the straps at or below your baby’s shoulder level.   Of course, you’ll need to adjust the harness as your child grows larger, so this isn’t a set it and forget it action.  You want to make sure your baby is safely secured in the straps every time you put him/her in the car!

check out this helpful video from the folks at monkeysee.com

Another factor to consider is the tightness of the harness.  Most people will do the finger test:  If you can fit one finger and no more under the harness, then your child is properly secured.  In order to double check whether the harness is secured properly, be sure that it is flat against your child’s thighs and shoulders.  You should be sure to position the harness clip so that it is flush with your childs’s armpits while the shoulder straps remain in the proper position.

If your child usees a booster seat, be sure that the shoulder belts are correctly worn.  Children will often tuck the shoulder belts underneat their arms because they get uncomfortable.  While this is understandable on the child’s part, it’s also quite dangerous so make sure not to let them develop a habit of doing this.  It also doesn’t hurt to glance back at your child once in a while to make sure he/she hasn’t repositioned the belts while you weren’t looking!  A seat-belt positioner device will be a great help when you’re trying to get the belts positioned properly and safely.  Even if your booster seat doesn’t come with the necessary positioner, you can find these devices on the internet to be purchased separately.  Even if you purchase one of the many cheap car seats available on the market, it should have the ability to be paired with this type of accessory.  Be sure to read your manual to make sure there aren’t any unexpected incompatibilities between your infant car seat and the seat belt positioners.  You don’t have to spend a lot of money to get a baby car seat cheap with the proper safety rating as well as options for using accessories!

Another practical consideration that a lot of new parents forget about when trying to save money by buyinh used is that the warranty on an infant car seat will not apply to a second owner.  Even cheap car seats are an investment in the future, and you want to make sure that you are properly backed up with all the proper documentation in case you should discover a faulty part on the device.  With a used seat, you run the risk of wasting your money when something breaks and you have to buy a new seat.  For this reason, it actually makes far more sense financially to spend just a little bit more money on cheap car seats that do away with useless features while still emphasizing quality of construction and complying with safety ratings.  This way, you get the best of both worlds:  Smaller immediate investment and peace of mind knowing that you have a quality product.

The last important factor is that a used seat will necessarily be a bit older.  Since the world of child safety is driving forward at such a rapid pace, you run the risk of not taking advantage of the latest developments.  There are many people who make a good living spending all their time testing out these products in real world situations, pushing them to their breaking point in order to ultimately improve the next version of the car seat.  You really should be sure to benefit from this research.  Again, you can still get a great baby car seat cheap without sacrificing the quality of construction if you just shop smart and don’t prioritize useless features that artificially drive up the price of the product.

All of this boils down to shifting your priorities as a new parent when shopping for child-related products:  Make sure to go with quality and safety first, and then narrow down the list to a product that has the fewest unnecessary, extraneous features in order to bring your cost down as much as possible!

Standard

If you are looking for a cheap car seat, you can cut down a bit on the price by purchasing a standard one rather than a convertible seat.  The standard infant car seat will generally last as long as your baby is under 20 – 22 pounds.  At that point, you may need to look at cheap car seats anyway because they are generally rated for higher weights.

Another nice thing about the infant only seat (another name for the standard seat) is that such units can often be mounted in a stroller and double as a travel carrier.  If you’re trying to save money in the long run, this type of cheap car seat may be the best investment.

Convertible

A convertible car seat is one that you can face backward for the first year, and then turn around to be front facing during subsequent years of your baby’s development.  Remember, a baby’s body is not developed to ride in car facing forward until they are 1 year old or older and at least 20 lbs. in weight.  The convertible car seats generally don’t have the ability to be mounted in a stroller like traditional infant car seats, but they do have some other advantages that make them worth consideration, such as better car mounting options, higher shoulder bars for older babies, and a number of other features.  Cheap car seats (convertible or otherwise) can be found for a pretty good price on the internet, so it’s worth your time to shop around and find the best possible deal out there.

So What Should You Ideally Choose?

I think that the ideal situation is to go with the standard infant car seat for the first bit of the baby’s life, and then move over to the convertible option when the baby is old and heavy enough.  The feature sets that you can get with the convertible seats (which can’t be found on the standard ones) are definitely worth the money if you can swing it, and since you can find a car seat with high quality parts and affordable accessories such as seat covers, you can be financially responsible while maximizing your baby’s safety and comfort.  Plenty of brands offer affordable options.  For instance, you can even find a cheap Britax car seat!

So what should you be looking for in cheap car seats?  Let’s take a look at some important factors to consider:

Adjustable Belts

Look for a car seat that will allow you to adjust the buckle from the front rather than from behind.  It can be a real pain to dig behind the seat to make a last minute adjustment, especially when time is running short and your child is already strapped in and ready to go.

Simplicity of Use

The nice thing about some of the cheap car seats that are available on the market is that they are simpler to use as a result of having fewer extraneous features.  Again, the safety rating of the car seat is what you don’t want to sacrifice – extraneous features that are there just to drive up the price of the car seat, however, can be dispensed with in favor of spending a little bit of money on reliable quality.

Ease of Cleaning

Let’s face it, any accessory or device that involves a young child is going to get dirty pretty often.  You definitely want a cheap infant car seat that is easy enough to clean.  It’s not like you need to search far and wide for something that will self-clean or anything crazy like that, but it does make good sense to find a car seat that allows you to clean it quickly.  Look for removable cushions and an absolute minimum of nooks and crannies that are nearly impossible to clean.

So Now What?

Once you’ve taken these basic things into consideration, you’ll want to look for further safety features.  I recommend always going with a safer option:  Get the seat that comports with any regulations on child safety because these will generally be there for a reason.  There are lots of very smart people who do nothing but test out products for a living, and these experiments are the driving force behind the sensible regulations that go into effect.  Do your due diligence and be informed on the safety guidelines, even when looking for a cheap toddler car seat!