If you're on Facebook, Fetching Tags runs contests quite often... if you participate, you usually can end up with a gift certificate code (usually ~$10 off a tag), which brings the cost to under $25 for a tag.
I love Fetching Tags and they're super sturdy.
I like the look of the Mad Dog Metal tags, but I'm not sure how sturdy they are. If anyone on here orders one, I'd love to read/see a review on them. I'm hoping Devi comes out with a brass option for tags in the future because I really want some brass tags for the chis- and the Fetching Tags in brass are much too heavy for them.