The other day I walked into ReTail and found Biskit there. Biskit really needs a ranch armchair, and I had one, but it wasn't up in ReTail yet. I placed it there, but I couldn't get him to ping to purchase it. Is the game really programmed so that the villagers will only buy items that were already there when they came in? I eventually gave up and mailed it to him, but I was surprised. I just haven't had the right items handy to test on another villager - I usually keep ReTail too expensive so that they don't put random items in their homes.