So I think I'm ok with the buying part, at least in the lower end of the "ladder"

It's the selling part that stumped me right now. To sell on eBay means I need to wait for a month to get the money back to grow, so even though it has a large pool of buyers, it's not good for this purpose. So selling local is the best way to go

Finding buyers is the challenge I have right now. Not sure how to go about doing "buy here, sell there", which I assume something like if I bought on Craigslist, I should sell on another platform.

Gordon, in your example in another thread here, you mentioned places like dry cleaner and alterations. Did you contact them and ask if they buy used drapes? Or you just use them as part of that network to find more sellers?