If the used one is in a good condition, why not. Most probably it is in a good condition as the car seat may only be stationed at the car, so not alot wear and tear.. do check first if getting the used one.
Better to get new or from reputed brand as u want to ensure it’s in good condition and has the necessary certification to provide the protection for your child in event of accident.
I bought mine from mothercare (house brand- Mothercare) below $100. So far so good. But i heard Graco is a good brand but shld be more exp😊
Get what is comfortable within your Budget range, search on carousel. There are lots of choices. :)