Credit cloning

The strategy is simple. 1) Move all objects in the shop to a single pile. Drop a cursed item to prevent your pet from moving on to it. 2) Drop gold into the shop. The shopkeeper will give you credit for the gold. 3) Let you pet steal it for you. 4) Buy an expensive item (if the shop has a more expensive item than what you have). 5) Sell and buy it repeatedly. All buys use the credit while all sells result in gold. 6) Once you don't have enough credit to buy the item leave it on the pile. 7) Drop the old + new gold in the shop and repeat from step 3.

The strategy can be time consuming.