(I've never seen a mulligan option either)
I posted it as a random thought in another thread, but I'll put it here since this thread is already near the top ...
Measured as a % of the 3-ball sleeve price for a 75 ball bucket (roughly the standard large bucket in my area) ...
What would you be willing to pay for a driving range/practice area?
Actually, it would probably need to be 5/10/20 credits + x% of the ball price per bucket to allow for the "cheap balls"
If people are willing to pay for practice, would it add some revenue incentive for a "choose your drop spot" function?