15pk Machine-Washable Stair Treads $21

This Bungalow Rose 15-Piece Machine-Washable Stair Tread Set drops from $48.99 to $20.99 at Wayfair. That's the lowest price we've seen to date. We found similar sets with only 7-10 treads selling for more at other stores. They feature nonslip rubber backings so they stay in place. Shipping adds $4.99, or is free on orders over $35.