If you want to buy a house, it's common to get a real estate agent. Your realtor will search the market, do preliminary inquiries, etc. If they close the deal at a price you will accept, they got a commission.

Why does nothing like this equivalent exist for purchasing a vehicle? A specialist who will search available inventory, enter into initial negotiations with sellers and dealerships, and if they come away with an out the door price that you will find agreeable, they get their commission.

Or maybe this DOES actually exist? What is such a person called, if that's the case?

EDIT: apparently these are "car buying agents" or "car brokers" ... so now my question to the internet is: who has had a good experience with one?