There’s https://bookshop.org for injecting modernity into supporting independent bookstores. It doesn’t help specifically for used book stores however.
I find the bookshop.org model a bit weird. There's no real reason that independent bookshops need to be part of it, apart from a marketing angle to court people who want to "help local bookstores" over Amazon.com.
From a recent NYT article on the site:
"Orders are fulfilled through Ingram, a large book distributor, and mailed directly to customers, so stores don’t have to have the books in stock or process inventory. Bookstores get 30 percent of the list price — less than they would typically make from a direct sale — but don’t have to pay for inventory or shipping."
Yea I don't fully understand it either, to be honest. Also it's interesting because in a recent HN discussion about Jeff Bezos courting early investors, the second employee of Amazon showed up in the comment section (https://news.ycombinator.com/item?id=24245909) and he mentions Ingram:
> I remember that not long after we "opened the doors" to the public, we had a visit from some reps from either Ingram or Baker & Taylor, the US's two biggest book distributors (I forget which). Part of the reason Jeff had picked Seattle was that it was within the 1 day delivery radius for both companies. These guys came over to see what we were doing and they were completely flabbergasted. They could not believe that a few people in a small commercial building in Seattle had built what we had already done by that point. They had no idea of the technologies involved, they had no grasp of the vision. But we never had to convince companies like this - we just ordered books from them, as their customers, and then sold them to ours.
In some ways it's like Ingram is striking back at Amazon, and sharing part of the proceeds with independent bookstores. My current feeling is that it has its place. I don't want Amazon to accumulate even more control and kill the diversity of businesses that make up our society.