Amazon offers Prime members the Cap Barbell 40-lb. Adjustable Dumbbell Set
, model no. RSWB-40TPB, for $39.99
with free shipping
. (Non-members can spend $49 or more to qualify for free shipping; otherwise, shipping costs $20.62.) That's the lowest total price we could find by $10. It includes two handles, four 2.5-lb. plates, four 5-lb. plates, four collars, and a plastic storage case.