This shop has been updated.  Money is now automatically deducted from character sheet.  It checks for enough funds before assigning items.

This extension allows a GM to create custom Shops and export them into their campaigns.  You name the shop, you include the shopkeeper in the window and you stock the shop.  Once shared you place the shoppers token(player) into the window and the player drags whatever items he/she wants into the purchase window.  The GM adds the players money to the till and hits the purchase button when the player is ready.  The extension calculates any change given, depletes the shop owners available items and automatically loads the items into the players inventory!

*** Please make a LOCAL copy of your shop if you import it from a Module***

https://www.youtube.com/watch?v=6tLEH3QTCSU&lc=UgxYTvk1MISWi0bJGQV4AaABAg

Update: 
https://www.youtube.com/watch?v=FYBwLFQbZVE

Added buttons for players to use to adjust inventory.  Also buttons should hide to prevent players from buying negative items.