You can save a bundle and do your own sandblasting. I used to sandblast granite all the time -- it's easier than saying "quahog quarters converted convection". Put the item to be sandblasted in a convenient place, where the dust created won't get into the environment (a living room is perfect). Get yourself some fine, dry, sand (white is preferred, but not necessary). Into a soda straw suck some sand, and blow it at the item to be sandblasted just as hard as you can. Pinch down the end which is not in your mouth for a finer stream -- a "bendy straw" can get you into those hard-to-reach places.

WARNING: Do not keep the sandblaster on one place too long or you can sandblast right through the object. Also, don't inhale through the straw.