Here is a burning laser that I built nearly entirely from old computer parts, power is around 250mW. The power supply, multiple heatsinks, and laser diode all came from a computer. I had to pay for the Aixiz module and LM317 + resistors, but that only cost a few bucks. Before throwing away computer stuff, take a look inside and salvage the useful stuff! I’m also powering my 1200mW Blue laser with an old computer power supply.