The items being sold would have a a time limit on them and a fixed number for sale depending on the item (this is posted in my explaination, first post). This may solve the problem you're talking about, though I doubt this will change the price of items, people will still buy for the same price as they always did. Those 40 as you say, though I doubt there will be this amount for the item(s) of the month, would have just bought the items for that price and will more than likely just sell them for the normal price, if they wanted to. That being said I meant for this system to be used for those that actually want to keep the item rather than them being sold off.
I actually missed you saying they want to make a quick profit. Well this could be done and it very might well be done but I doubt everyone that bought the item would look for a quick profit rather than waiting a few minutes for a profit much bigger. And even if they did get this profit this will not change anything, those why buy it will just sell for the normal price as they always do resulting in no change.
Didn't bother looking over this so you can tell me if something confuses you/ doesn't make sense.