I have a set of 500 lb scales that I got for $50, and a kitchen scale that weighs items up to 8 lbs. I have a price list that I and my customers are happy with. Some things I am cutting it close on and others I do really well on. The best is to see if you can get the stuff for free, most places wont do that even if they are throwing it in the dumpster. Computers, I buy by the piece, start with a price that you can make money on and deduct for missing items. Laptops I have a per piece price as long as the motherboard is there, if no mobo it goes in the pile of stuff I don't buy but they still want gone.