In the current build, I fixed the arbitrage problem (mostly) by eliminating the difference in pricing between random "sneaky" merchants and stalls under rpg items, and bringing the store price premium down. However, I left is so that there is a small 5% difference in store price, so technically with a perfect 10 in commerce you could make a few coins shuttling stuff back and forth between stalls and shop, but with the random traders using stall prices now, you would barely make anything doing this. So that part is not really a problem, but there is still room for further improvement later: A)disaggregate buying and selling price bonuses, so that stores sell for a higher price, but buy stuff from the player at the standard price. B)make it so that the high end gear and especially item bonus books and special equipment is rarely available outside the store, so that players have an incentive to shop at the pricier high end place C)probably rework the item amounts and variety from the different merchants As a general plan, I'd suggest: 1) Make the "sneaky" encounter walker merchants (note, these are NOT the guys who sell thief stuff, sneaky is just what the file calls them) have very few items, but of very high quality, especially skill bonus items. So they don't carry 50 swords in their cloak, but are very nice to run into. 2) make the stalls have a variety of normal equipment, but not much of each item they have (these are configurable seperately in the file), so they reflect a sort of assortment of whatever the owner has to sell. 3) make the stores have high quality stuff, lots of each, and large variety, but a large price premium for their sale price only (not for what they pay the player), so you are paying for convenience and access, like in real life shopping at more expensive store.