This guide will show you how to set up your own shop.
Create a ChestShop with Buy & Sell
If I want to sell 64 (1 stack) of cobblestones for $64 and buy them for $32 then I'll create a sign in front or top or bottom of the chest that would contain the cobblestone items to follow the format:
so to sell 64 cobblestones for $64 and buying them for $32, I would do this:
You can also replace Cobblestone with ? and it will auto-fill for you based on what's inside the chest. Your chest must include something for this to happen or it will not update the sign.
Create a ChestShop with ONLY Buy or Sell
To sell 64 cobblestones for $64 with no options for players to sell them to you, do this:
As you notice the : 32 S part is missing. That's how you only enable the buy part. You can do the same for sell only by just displaying 32 S instead.
Here's some examples of how you can link up the sign to the chest in different ways: