So I was looking at how to store my dry goods and I was pricing those tall containers that roll. They are like $80!!! Then I went to go feed my dog and realized the container the food is in is actually the same size as the one I was going to buy for $80 except it's $18!! Am I crazy for thinking about using these for food storage?? I mean it should be food safe since it has dog food in there

I don't think you are crazy at all.  If the $18 container gives you a nice seal so things stay fresh (which it should since it would be keeping dog food fresh) then I would 100% go with that.  A dollar saved is better than a dollar earned right?! :)

Does it matter if it was not specifically designed for the particular purpose?  A rose by any other name would smell as sweet!  Example, I use electric fence wire as armatures for my sculptures all the time.  It cost a fraction of the armature wire sold in art supply stores and works the same.

Not exactly on subject, but this weekend I found a 12-pack of 3/8" diameter 32-inch long skewers in the camping section of Walmart for 88-cents!  They will make great center dowels for this hobby baker.

Great find, crnewbold!