The shop is a place where you can purchase and sell some items, and where you can fix items. Once you have initiated contact with the shopkeeper by clicking the shop with the left mouse button, you need to place a bag of gold in his right hand.
From there, you have 4 options.
Buy Item
Purchase an item. A shop might not sell all items, so you may have to find another shop to purchase something specific.Sell Item
Makes the shopkeeper offer you gold in exchange of the item you have put in his left hand. They don't buy everything. It can be cheaper to fix an item before selling it.Fix Item
Fix the item you have put in the shopkeeper's left hand. This is for items that have a life percentage, like a Sword or Dev-Scape that will explode if their life reach 0. Items not sold by the shop can still be fixed.Fix Player
Fixes the parts of a droid.Tip:You can click directly on the shopkeeper to go back in the chain of menu sequence instead of using "Main Menu" which is a bit harder to point.
As mentionned in the "Tips and Tricks" section, you may want to leave your
heavy bag of gold in the hand of the shopkeeper because it is shared among
all shopkeepers. The lighter you are, the better. Just don't forget to
pick it up before leaving the base!