Where can I find a CDL Class B Bus with Air brakes to Rent for Practice and for CDL Testing in Philadelphia?

So I have some friends that wants to get there CDL Class B without having to go to school. Now I have my CDL Class B, but i went to All State career trucking school. My question is when i first got my got my permit by PennDot it had a test for each Endorsement, CDL General Knowledge, Skills and Air brakes, and then my Endorsement, P=Passenger and N=Tankers. Now i can easily train my friends on how to drive a CDL Vehicle with the Pre-trip, Skills and Air brakes but if they want to get they're P endorsement license to they need to have a bus or can they have a Class B truck with Air Brakes; and if they need a bus, are there places i can rent one because all ive seen were bus companies renting them with a driver, not by yourself.