Try looking at some local autoparts stores. Not AutoZone, but the higher end performance type places. A lot of them do light machine work and use a bead blast cabinet.
Here's what I've done a couple of dozen times over the years. I'll get a six pack of beer (or carton of Cokes) and knock on the back door of the shop at lunch time. The guys will be happy to spend a couple of minutes bead blasting whatever you have (usually gun parts or knifes in my case). I've used 4 or 5 places as they've gone in or out of business or moved. Just make sure the media they are using fits your purpose.
A cheap, fast method that's worked for me.