My garage is unfinished. Cans sit very well on the 3 1/2" side of a 2x4.
I nailed some 2x4's between the studs and set them on there. Kinda hillbilly, but, it works perfectly and makes use of room that would otherwise be unused to me.
Remember can height- There are about 2 sizes. The "normal" height of a spray paint can and the "taller" height of something like CRC Brakekleen. Make your storage plan to accomodate different heights.