If you want to do the leg work I would check some of the hardware stores that still carry sporting goods. Sometimes they dont sell enough and have to get rid of the older stuff. I have scored on steelshot for 7 to 9 dollars a box on occasion. Its not a sure thing but its out there.

I thought Cabelas had a decent price on the case but they would not let me mix and match the shot sizes I wanted. I did not want ten boxes of all the same shot size.