I've got some cheap Caldwell protectors,
http://www.cheaperthandirt.com/38620-46371-966.html
They're not great (I don't like the lag time between when there's a shot and they come back "on-line", about 2 seconds), but they are supposed to reduce noise by 27db and only cost twenty bucks.
Some day I'll get some better ones (probably Peltors), but in the meanwhile, these are better than the passive hearing protectors I was using before.