We all have it - that random expertise in some obscure niche field that we think will only pay off when we appear on Jeopardy. But ... well ... you never know. Just a little bit of knowledge can sometimes pay off!
I happen to know just about everything there is to know about ink cartridges. Maybe that was a little prideful of me to say. I'll rephrase: I know a lot about ink cartridges. I know what they're worth, how to use them, how to talk about them, and how to tell other people about them. I know brands, types, problems, troubleshooting, and durability. I can clean, refurbish, refill, and recycle like it's my job.
Maybe you don't know much about ink (I mean, who does? Oh, yeah. Me.) But maybe my ink cartridges are your power tools, or textbooks, or hand-woven ancient Incan baskets. Whatever it is, there's something you know a lot about.
You can look for these things on super-duper sale. You can talk to your friends who are getting rid of them. You can look at ads on craigslist, shop garage sales and thrift stores, and pick things up off the side of the road. Don't forget: you know about these things. You're an expert. Clean them up. Make a good assessment of them. Then list them on ebay or craigslist, find a local shop that will pay you or swap your items for store credit, or network with folks you know to find a market.
If you do this once a month and make $20 off of your expertise, that's $240 you'll make in a year that you weren't planning on. Wait ... that's almost enough to get this!