Rotopax without bed rails?

Anyone have a pro tip about mounting a couple rotopax jugs in the back of the bed? I have the 8 ft bed but no bed rails, hoping for an easy/cheap way to do it without them.

 

Buy a normal 5gal jerry can from CalRanch or a power sports store, and use a ratchet strap This is Pro in many ways, you get 500% more capacity than a rotopax, you save about 500% in money, you can flow 500% more fuel and not spend half a day pouring one gallon, and they're easy to tie down. Wins all around!

 

You can make your own rails out of unistrut and then bolt it to them.

 

This, but then do as the other poster sugggested and do not waste your time or money on Rotopax. I could see a valid use where space is limited but that's just not the case with a truck.