If you lived near the ocean you could feed bait fish. In Mexico we would just throw a net and have a few hundred anchovies. You could probably find them really cheap if you're in an area on the coast, and if legal you could just toss a net near a pier and get some yourself.
It's a better idea to feed frozen pieces of shrimp, squid or whatnot. They are easy to find and cheaper if you couldn't catch the fish yourself.
Display tank - 24g nano w/ softies/montipora
I run electrical appliances underwater and enjoy injecting things with Kalk filled syringes.