I've used these. They are pretty good. Not sub $100, but you can shop around and see if you can find them for less. The "output on" button is handy to pop the voltage on/off to your circuit without having to power the entire unit off.
https://www.sparkfun.com/products/9291
I personally own a Mastech, it's okay. It's a bit tricky to use because it jumps from Current Regulating to Voltage Regulating. But this one is cheap... http://www.amazon.com/Mastech-Single-Output-Power-Supply-HY3003D/dp/B004ISQ270/ref=sr_1_1?s=electronics&ie=UTF8&qid=1445227930&sr=1-1&keywords=mastech+power+supply