Replace parchment paper or wax paper with a reusable, washable baking mat. Place the mat on any pan to make it a nonstick baking surface. Crate&Barrel's model, on sale for $12.71, is made of silicone-coated fiberglass, is dishwasher safe, and rolls up for easy storage.

Crate & Barrel
Instead of replacing cookie sheets buy a baking mat, and turn any old pan into a nonstick baking surface.