You may notice that each of these suggestions is getting a little more involved. Don't let that scare you away! These are just some ideas of things that have worked for me and for The Strategic Homemaker. Hopefully they can be a springboard for you, too!
I'm calling this a "break-up," but I promise it's not sad! In fact, this might be the happiest split you've ever heard of. But it does require knowing a little bit about something specific (dare I say, a niche?), and keeping tabs on local for-sale ads (like Craigslist).
Start looking at ads where people are selling "lots" of things. I don't mean "a lot" of things ... I mean, someone who says "take the whole lot for $___". These are sellers who (a) don't know the value of what they're selling, (b) just want to get rid of something, or (c) want cash soon. These sellers are your friends.
Compare what is in the lot to the value of each individual piece. At first it may seem overwhelming, but with a little bit of practice, you can get in a groove and really understand when a great deal comes along. You can use eBay or Amazon to help you find the general retail and resale value of an item.
If you find a "lot" for sale where the asking price is WAAAAAY cheaper than the combined price of each item, it will probably be worth it for you to buy the whole lot, split it up, and sell the pieces individually!
For example, a few months ago I saw a for-sale ad ... cloth diapers for $100. One hundred dollars, you say? That's a lot of money! Until I looked at what the seller had listed ... over 70 diapers, in excellent condition. She was moving. She had a 2 year old. She didn't need them! So I went to pick them up that very day.
It turned out to be very much worth my while to fork over my own hard earned dough. A valuable break-up, indeed!
PS. Maybe you're thinking, "I don't have time in my day to follow everything on Craigslist! You must spend hours there!" Nope. I just have my things I watch. Maybe your things are garden gnomes instead of cloth diapers or ink cartridges, but it's quick and easy to just follow one thing. Try it and see!