Not a bad list, though your rarity 5 item could be better. Tombola stamps consistently stay at 1mp far more often. Bronze gumballs fluctate every now and then. Actually, all gumballs tend to. Though when I'm feeling lazy, I use them. You can check my cheapest poison pit items list for items that often stay at a fixed price: http://www.marapets.com/blogs.php?entry=399427&id=532146