I have a Rosewill power supply tester: http://www.newegg.com/Product/Product.aspx?Item=N82E16899261023&Tpk=rtk%20pst
Inexpensive, well-built and easy to use. The issue with PSU testers is that there is no load on the PSU; it simply turns the PSU on and tests the voltage on the rails. It can tell you if the PSU is DOA and the status of the rails not under load. Under load could be a different story. Get a good quality PSU and you don't have to worry about it damaging your parts on the first boot.