I have ordered these and they are nice. They are done by a person in Atlanta.

Here is a link that might be useful: Corian plant markers

The best prices I've been able to find are on ebay. I like the taller copper one's that you can push pretty far down into the ground. I write the plant name on with a ballpoint pen to permantely indent the name in, then I usually go over it with a grease pencil so it's easier to read. I borrowed a Brother p-touch label maker last year and stuck the UV resistant labels on top of everything so there should be no losing plant names anymore...I am completely out of tags so need to go there and search for more. Need to invest in my own label maker soon too! :)