Walmart has the Mainstays Extra-Firm 100% Polyester Pillow (Standard/Queen) on sale for $5.00 with free in-store pickup. Otherwise spend at least $50 to skip shipping and handling costs.

This only has a few reviews but they are positive. This pillow is great for back and side sleepers. It is 100% polyester and features hypoallergenic fiberfill. It is machine washable.