Its always good to get some tax relief and retain the majority of your earnings when you invest. Tax exemption is even more important if your receiving dividends. As a result below are some good options.
Vanguard Tax-Exempt Bond ETF (VTEB); Currently Trading at $52
iShares National AMT-Free Muni Bond (MUB); Currently Trading at $111.00
SPDR Nuveen Barclays Municipal Bond ETF (TFI ); Currently Trading at $49.00
There are some other great ones you can find. Pay attention to the yearly returns and fees which could eat away at your returns.