Every day, tons of electronic parts are simply discarded. What most people don't realize is that many of these parts are still in working condition. They can be sold individually for a profit, or dismantled and put together into a whole working piece of electronic equipment. Your start-up costs can be anywhere from $200 to $1,500, depending on how much time and work you want to put into it. This can either be a hobby or a lucrative main business.
Choose a specialty. Unless you're an engineering major, it's generally not a good idea to try and make money from many different types of electronics. Instead, learn one type well. For example, if you concentrate on PC scrap parts, you'll soon learn what each part is worth and how to put together custom PCs.
Visit your local scrap yard. Generally you'll either get to enter for free and pay per part, or pay a one-time entrance fee and take as much as you like. There are many electronic devices that are simply thrown in the garbage with parts still working. Scrounge up as many parts as you can and bring them home to test to see if they work.
Purchase parts from eBay and/or Craigslist. Buy individual parts if you believe they're underpriced, or buy broken electronics. For example, someone might put a "broken PS3" on Craigslist for $50. You could replace a single broken part for $20, and then sell the PS3 for $200. Alternatively, you could take apart the broken PS3 and sell the parts for $100. Again, you will need to know one specific type of electronics well so you know how to price it.
Catalog each part. List your working parts on sites like Craigslist and eBay if you can sell it at a profit. Any time you have enough parts to build an entire working model, build it and sell the whole. You'll generally make more selling a working piece of electronic equipment rather than its parts.