Does CarGurus take a percentage? If so, From seller or buyer?

I believe it is a flat fee that the seller pays.

There is a $29.95 fee that was recently added so that sellers could use our secure checkout platform when completing the transaction! This fee is applied per listing and as part of this service, you will get: the funds verified before you hand the keys over to your buyer. assistance from a dedicated agent. a bill of sale generated for you and the buyer to electronically sign. the funds securely deposited directly into your checking account.