Our son Joe goes to the batting cages every week to practice his hitting. He's playing baseball in college now and needs to keep practicing.
The staff at the batting cages recognizes him and he always uses a coupon—buy 2 rounds get one free—downloaded from the web site of the batting cage (actually a large fun park near our home with go carts, bumper boats, golf, mini-golf, batting cages and volleyball courts). The coupon has no expiration date on it.