transition car seat recommendations

I already have a transitional one for my car but I'm looking for something cheaper for my mom's car. After 3 months when I go back to work she'll be babysitting. I want to get her a cheap/good one for her car. That way I can leave mine where it is. We are using an infant carrier and base so there is no rush whatsoever. I just like to be prepared. Any recommendations would be great! Thank you in advance 😃👍🏻