I know there's a lot of different sites out there to sell books back to, aside from Amazon, and I am an affiliate for Cash4Books. So I knew what she was asking about. I also know from experience that my treasure trove of romance novels aren't really in demand, so I never really made any money back selling them.
However, the premise of Bookscouter is that it will scout, literally, for the best price among an array of book sell back sites. That helps you find the best price for what you do have. To really eke out some cash, you'll need to either find books for free or very cheap. Goodwill prices vary widely and $3 for a text worth $3.50 might not be the best way to make money since you'll be laying out a lot of money and remember, too, that your time is worth money took. However, if you have a high volume store that sells paperbacks and hardcovers at a reasonable price, you might just do OK after all.
Pinching Abe does, from time to time, include referral links and/or affiliate links within the body of the text. Please be aware that clicking on any of these and/or shopping through those links may benefit her by way of earning money toward a commission for referring you to specific deals or sites.