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Here are some deals on carseats.
Amazon has their #1 best seller, the Graco Nautilus 3-in-1 Car Seat, for $130, when you choose "matrix" design. No, the Matrix design won't make your child the next movie star. But, it may just keep 'em safe in a collision.
I know many people prefer to be able to transport baby around in a carseat and then lug them into the house and then into a stroller with the same thing. That, is, of course, someone's choice. But, do know that baby gets heavy with the added "seat" weight and that it isn't good for young babies to be in that position very long. Instead, choose a seat that stays rear facing for a while (2+ years, 35+ lbs) and you'll save money too.
The Graco Size4Me 65 Convertible Car Seat holds a rear-facing infant from 4-40 lbs. and forward-facing child in its 5-point harness from 20-65 lbs. Choose Nyssa color and save.
Your car also matters. If you will be rear facing, and have a compact car, consider a carseat that may be "shorter"
The guide 65 is a perfect fit for smaller cars and helps protect your child longer. Rear-facing 5-40 pounds and 19 inches-40 inches Forward-facing 22-65 pounds and 34"-52"
Installation is a major concern as well. It is important to read your car's owner manual as well as the manual for the seat so you can get a proper install.
ClickTight Installation System is the safest and simplest technology on the market; Open the front of the car seat, buckle the seat belt across and click the seat shut; That's all you need to do for rock-solid installation
Another concern for many is getting three seats in one car.
Yep, it can happen. Consider the Diono Radian for that issue or just if you have a compact car (it may not work well rear facing with a tall driver). Also, it goes from newborn to 100 lbs, so it really can be "one" carseat. Some may claim to be able to do that, but have a 5 year expiration. Most Radians are built to last 10 years. They're heavy though.
Which carseat do you have?