I'm thinking I could save some money by finding used car seat bases.

We are having twins and are planning on getting 2 additional car seat bases (chicco key fit). They retail for $80+ each. I could get them from my MOM (mother's of multiples) group for $25 each.

Anything I'm not thinking of? Safety? Do they expire like car seats do?

Oh, I'll make sure to ask if they are free of any accidents.