You’re right—parchment paper is an expensive product. Although parchment makes it easy to remove cookies and other baked goods from baking sheets and almost eliminates cleanup, the product is a luxury. For most kinds of cookies and baked goods, nonstick cooking spray is a great inexpensive alternative.
Save parchment for delicate cookies, such as macaroons, meringues, and thin cutout cookies, where its perfectly nonstick surface will help eliminate breakage.
And when you do choose to use parchment paper, remember that it can be used more than once. It can be used as many as three times; although it becomes a bit brown, it still does its job, even when used repeatedly.