Walmart offers the Camp Chef HWD5 Triton Hot Water Heater for $92.77. Opt for in-store pickup to cut that to $88.50. (Amazon has it for the same with free shipping.) That's the lowest price we could find by $41. It heats 1.5 gallons per minute and features four settings and an adjustable water temperature range of 80 to 150°F.

Update: It's now out of stock at Walmart; however, Amazon still offers it for $88.50 with free shipping for Prime members.