I bought my grommets at Hobby Lobby. You need to make sure that you get the kind that will just snap together, or else you will have to buy the machine along with it. . .and that can get expensive. The ones I bought are plastic, but once you get it on your curtain, you can hardly tell. It came with 8 grommets, to do one panel. It also has this nifty little measuring tool to help you get the right sized hole.
I did my holes about 3 1/2 inches from the top and about 9 inches apart. I also cut my hole a little smaller then the outline. After doing the first one, I noticed that I didn't need to cut the hole quite so big. I used pretty heavy fabric-singled, but there was plenty of space and the snapped together very nicely, so if your worried about thick fabric, don't be-it works great!
