Regarding the scenario you described, if Minnie is to tranfer money to Mickey, the item needs to be listed at the lowest offer at the market in order for it to be bought (usually 1 below the current lowest price). If say there are already 40 listed at 1000 silvers at you place yours at 1000 silvers also, it will not get bought until those listed above you are sold first (if the owner does not add extras of the same item at the same price).
> Mickey puts that item on the marketplace for 2000%. and Minnie waits for price to come down to 2000%. By the time it finally shows the 2000% as the lowest price there are 8 of that item.
The only possibility of that happening is someone watching the market very closely and placing their items with the one you dropped. Although your item would still be at the top of the buying order, so buying one would most likely be Mickey's (unless the person buys your one and now owns all 8).
If you're finding it hard to transfer with the presence of other similar items on the market, why not buy out the lot (usually goods all listed at 50%). This often appens when it has been listed by 20 different characters (and bumps off the higher listed price items). In this case, simply list at the highest possible offer. For example, there are 600 odd disprosiums on market at 50% each, buy them out with Mickey and list at 75000 each, next buy with Minnie.