Using a broker

[elonblock]

Hello,

A local guy wants me to help him sell his car, because he is not online . I know how to sell cars online successfully, as I have done it with my own vehicles. However I have never sold a car for someone else and been paid for my services.

Could someone explain how a broker works.
What are the brokers responsibilities, and what do they charge?

For example do they screen the prospective buyers and do all of the negotiating for the seller?

Thanks in advance,

Elon