Do you have any collections you wish to part with? Or anything you don't need anymore and would like to turn it into cash?
If so, consider selling on eBay (or Craigslist--although, I admit, I've never sold anything on Craigslist so my knowledge of Craigslist is limited).
The first thing I'd do is find out what similar items are selling for.
Items you think will sell well may not. I have plenty of stuff from when I was a kid that I thought would sell well but never did.
For example, growing up I had a rather large collection of National Geographic magazines, complete with the leather vinyl slipcases.
They didn't sell.
I take that back, I did sell one years worth, but the money I got wasn't worth it, in my opinion, so I turned my efforts elsewhere.