Speaking of expired domains, in your case the domain might have not been valuable enough (not enough backlinks). But I recently saw two websites put up for sale, one was claimed to be making $4000/mo and the other $1000/mo. Both from Amazon affiliate links.

The weird thing is that neither website was in the same niche as to what it was "reviewing". For example, the resort website had a post about the "best tomato chopper". Some of the old content was kept though(taken from archive.org), probably to look more "legit" to Googlebot.