2-Pack Reebok Adjust-A-Weight 12.5lb Hand Weights $40, or Reebok 25lb Adjust-A-Weight Hand Weight $40 + 99 cent shipping ($67+ on Amazon)

99 cent shipping with code SUMMERSHIP99

Reebok® 25 lb. Adjust-a-Weight [gaiam.com] $40
*nice reviews on Amazon [amazon.com]
Strengthen your upper body with this convenient, adjustable dumbbell. This easy-to-use dumbbell adjusts with ease in 5 lb. increments from 5 to 25 lb. With a comfortable hand grip and easy-to-use dial. Move the weight selector dial on each side of the dumbbell to your desired weight and start lifting. 25 lb./11.33 kg. China.

Reebok® 25 lb. Adjust-a-Weight Set [gaiam.com] $40
*not so nice reviews on Amazon [amazon.com], however, Gaiam offers 100% satisfaction guarantee here [gaiam.com].
A couple more encouraging reviews here [fitnessequipmentexpress.com].
**I believe the description is wrong here-picture shows that each weight goes up to 12.5 lbs/totalling 25lbs, vs. 25lbs each like the one linked below.
Strengthen your upper body with this convenient, adjustable dumbbell. This easy-to-use dumbbell adjusts with ease in 5 lb. increments from 5 to 25 lb. With a comfortable hand grip and easy-to-use dial. Move the weight selector dial on each side of the dumbbell to your desired weight and start lifting. 25 lb./11.33 kg. China

Seems like there are other potential fitness deals to be found in their sale section [gaiam.com], for those interested.