It's quite possible to make money riding a courser, but you'll have to be naked.
I use a courser, heavy lance, and cheap-ass cavalry sheild. I'm still able to make money, although you can't be on the loosing team for too too long.
If you desire armor or more money, rouncey works too. If you have high riding and are a skilled cav player you can do very well with just a rouncey.