Don't be cheap about it and burn your garage or your equipment up. I put a large addition on my second garage, which already had a 100 amp subpanel in it. I put a second 100 amp subpanel in the new addition. I have a 50a tigwelder, 30a compressor, 20a lift, lights, outlets, etc. No problems at all. The materials for the electric rough in, which included 4 lengths, 75' each, of #3 copper. I spent around $800. This was the wire, box, main breaker, all the other breakers, 20a tamper proof outlets. Everything works well, I haven't tripped a single breaker, and it was inspected and passed with flying colors. Don't mess around with cheater cords and the like, you're only asking for trouble.