Amazon offers Prime members the Black Mountain Therapy Exercise Bands Set for $19.21 with free shipping. (Non-members can spend $35 to bag free shipping; otherwise, it adds $7.24.) Outside of the below mention, that's the lowest total price we could find for this set by $3. It includes three therapy stretch resistance bands with handles.
A close price: Shop.com has them for $19.99 with free shipping. (Search "Black Mountain Products Therapy Exercise Bands" to find it.)