Here's the bucket I just put together. I like my (larger) Coleman cooler (posted earlier in this thread) and it does a great job even on small 'gills for catfish bait, but sometimes it's just too large. I quickly added-up in my head and have about $25 in this (styrofoam liner, air stone, air pump, new bucket and lid).
I'd made a post a page or 2 back about the liner having it's own lid, which I cut-out enough to retain the lid, and still have access to bait. It alsi gives me a place to keep a spare pair of batteries with the bucket.