I got a great deal on a brand new Ditting grinder. Even though I grind for me and my family, it is awesome, esp. when the occasional multi-pound gifts come up.
You can also find some Bunn grinders that even accept the funnel directly (I bought one from eBay used, and we are still using it at work with a Bunn Airpot brewer).
Both grinders were around $250, and the Ditting was by far the better value, but I think that was luck. There are 2 basic types you can go for: Supermarket grinders meant to grind into a bag, or ones that grind directly into a funnel.
Do a search on eBay for "Bunn Grinder", and make sure to choose "Completed Listings" on the advanced options. Now you can see what is out there, and what they go for with shipping after the auction is closed.
Craigslist is also a nice place to find some deals. I find that for drip, American or Swiss/German stuff is the best bet for drip.