If long US Treasury Bonds are overpriced, here is a low cost hedge suggestion against rising long-term interest rates with defined and limited risk.

iShares Barclays 20+ Year Treasury Bond (TLT) 112.73. This ETF seeks to duplicate results corresponding to the price and yield performance of the long-term sector of the United States Treasury market as defined by the Barclays 20+ Year U.S. Treasury index.