Woot offers PowerBlock EXP Stage 1, 2 or 3 for $129.99 free shipping with Prime. 

Product Description:
Stage 1
PowerBlock EXP Stage 1 Adjustable Dumbbells have a weight range of 5-50 lbs and replaces 16 dumbbells in the space of 1. EXP means expandable and you can expand this set later to 70 lbs and again to 90 lbs with optional expansion kits (sold separately). Includes two dumbbells. Includes two 2.5 lb adder weights per handle at no charge to micro-load weight adjustments. Patented compact design keeps your workout area neat & organized. Replaces 16 pairs of dumbbells or 825 lbs of free weights. Handle - the open draft of the interior surface maximizes the range of motion and increases ergonomics with the contoured rubber grip.

• Includes two dumbbells
• Has a weight range of 5-50 lbs per dumbbell
• Can be expanded later to 70 and again to 90 lbs with optional expansions kits (sold separately)
• Increments: 2.5 (adder weight), 5, 7.5, 10,15, 17.5, 20 25, 27.5, 30, 35, 37.5, 40, 45, 47.5 and 50 lbs
• Replaces 16 pairs of dumbbells or 825 lbs of free weights
• Dimensions: 12" x 6.5" x 6.5" (per dumbbell)
• This item ships in two boxes
• Model Number: 503-00186-02
• Imported

Stage 2

• ADJUSTABLE DUMBBELLS SET: Elevate your fitness and performance with strength-training equipment that adjusts with you. This PowerBlock Expansion Kit provides the option to take your 50 pound PowerBlock EXP Adjustable Dumbbell set up to 70 pounds.
• Stage 1 is required for use

Stage 3

• ADJUSTABLE DUMBBELLS SET: Elevate your fitness and performance with strength-training equipment that adjusts with you. This PowerBlock Expansion Kit provides the option to take your PowerBlock EXP Adjustable Dumbbell set up to 90 pounds.
• Stage 1 AND 2 are required for use