amazon.com has the AmazonBasics Rubber Encased Hex Hand Dumbbell Weight on for $28.49 with free shipping. Temporarily out of stock, but available on back order.

• Solid cast-iron core
• Hexagon-shaped rubber-encased ends help prevent rolling and promote stay-in-place storage
• Sold individually; weighs 25 pounds; backed by an AmazonBasics limited one-year warranty