Because our class is essentially a production facility, we use the top of the line models from Inland and from Glastar.
I used to recommend an Inland Wizling CG grinder, but the price on
them has gone up from less than $100 to closer to $130. New or used they are great. Used, just check eBay. Grinder bits come with new ones. They last 100 hours or so before they need to be changed. However, you can change the bit whenever you feel like it’s not sharp enough (when it's yours you can change
them every 10 if you'd like!) They should also come with a plastic wrap-around
“splash shield” and a face shield. Buy a putty knife/spatula for scraping out the reservoir as needed.
Here are a couple of lower priced ones I found that you might try.
Gryphon Gryphette Hobby Grinder $95 (cute, small, for light-to
Glastar Diamond Star Grinder $150 (good solid grinder for hobbyist)
Click here for the stunning array of choices.
In my classes, sadly, we have only enough in our budget to replace them every 6 weeks. We have 6 up and running almost constantly throughout the day. you can buy brand-specific ones, but I have found that most of the grinder bits out
there to be a pretty standard size to fit the motor shaft. We usually use 3/4" to accommodate smaller curves. Using 1" is fine too. We have one extra grinder
dedicated to having a tiny bit (1/4" or 1/8")
Here are my favorites:
Aanraku TWOFERS 3/4" 100/120 grit (You get two for somewhere
between $23 and $25. Good for us.)
Inland 3/4" Speed Grinder Bit (I'll set one of these up every once in a while, and they. Grind. Glass. Fast.)