I currently have a variable DC power supply, a cheapo china one 0-30v 0-5A that can be constant current or constant voltage. It's helped me a lot until my recent project where I need 12v at 30A. A brand-name variable power supply of this capability costs $250-$600 and I'm just a poor college student.
If I bought a $40 12v 40A power supply from Amazon or ebay or whatever, could a DC motor controller (PWM type) make that into variable voltage from 0-12V? Obviously there'd be no current readout or constant current capability, but I don't really need that for this project.