LightGui

This GUI interface is generated when you open the craft table

And it's mandatory. Don't ask me why I didn't set the option, because it's light (ok I am lazy - -)
Protocollib is required to run this plugin
Protocollib is required to run this plugin
Protocollib is required to run this plugin
Important words say three times
Here are three blocks to click on

golden carrot

This golden carrot is a cue block and has no practical effect
It means that just click on the item in the store, and if you have enough material in your backpack to trade, you will get it

red button

When OP wants to delete a product, put it in your hand and click the red box to delete it successfully

green button

When you put the product you want to add into the GUI, and then set the material that the player needs to get the product (put it in the bottom six squares), and then click the green box to save it

This is a very light plugin. It doesn't even set the command. Instead, it's all implemented by GUI. (I don't like commands personally. QWQ)
Oh, a thing I forget to say ,The plugin can even store NBT object

There must be someone who wants to change the language in the plugin. This is completely OK. Just change it in "message.yml" It's very convenient
If there are bugs or functions you want to add, could tell me under the comments