I needed new pet tags and road ID after moving. So I got a dog tag style with rubber edging to replace my road ID from
Dog Tags, Pet ID Tags, and Cat ID Tags from Love Your Pets
I have it on a carabiner that I have on or in my pannier, or on my seat post.
All in with shipping less than $12 for a dog tag, two cat tags and a rubber edge with first class mail. ($4.50 for dog tag and edging without shipping).
After almost 10 months the tag is in great condition, the rubber is a bit worn on the edges from rubbing on other keys.