Relax, folks. My pals and I were making and wearing these back in the seventies with no hassles from the Secret Service. A few evenings of TV viewing while tapping the rim of a dime with a common teaspoon resulted in an eminently wearable fashion statement. Those with larger hands used quarters. Todays composite coins don't work well at all. See, you can do anything at all with money as long as you don't try to alter it AND spend it. Just keep it to yourself or give it away. Try it, it is a satisfying way to spend otherwise wasted time.
The key word in the statute about coin defacement is 'fraudulently'. It's OK to mangle a coin, as long as the purpose isn't to pass it off as a denomination it's not. Otherwise those penny press machines you see at many souvenir stops would be illegal.
It's not nearly as cool, but if you don't have the time or energy to make a ring out of a coin - http://members.cox.net/crandall11/money/ring/ And here's some more money origami - http://members.cox.net/crandall11/money/index.html
Guys, it's not about cost! A ring out of government issue metal is awesome. And neat. That's priceless.
And here's some more money origami -
http://members.cox.net/crandall11/money/index.html