I use a steel trash can with a tight-fitting lid, lined w/ a big trash bag for 2-Row. I also have a 55# wheeled Dog Food Dispenser that I got on clearance at Sam's Club for $20 and store Pilsner in it, and it works great. I prefer the wheeled, rectangle form of the Dispenser, vs. the round, heavy form of the steel trash can.
Also you can use 14-gallon drums from eBay, or Vittles Vaults for $39 ea. However, I bought my 14gal drums as fermenters, not as grain storage.
Lastly, I keep my "large" specialty grains (5# rye, 5# munich, etc) in a big 40qt Igloo cooler when I'm not using it as, well, a cooler.