Sounds like a casual contract.
Sort of like 'friends with benefits'.
Good hitting partners can be very difficult to find.
One that's willing to help bring along you're game is a bonus.
If you don't mind my asking, what's the going rate in the D.C. area?
Friendly but commercial. $67 an hour at the YMCA, court included, no charge for rain days. A previous instructor went off to work for Donald Trump at a resort over in Virginia where he doubtless is getting more. When last greeted at the local Legg Mason tournament, he was looking very prosperous.
It's an extravagance, I know, but, by hitting all those balls and refining my other strokes, it is good for my other tennis, good for my partners' tolerance in those other games, and it keeps me in shape. I guess those are all benefits but that is not what the above phrase brings to mind.