Hi I would like to know because I would like to add two things. I would like to know if it is possible to check the skin id of the object in order not to be able to better manage my personalized objects. Example: one fuse = 5 coins and one fuse with idskin 598542652 = 100 coins.

Second thing, I saw that you added the possibility of executing commands. Now I would like to know if it is possible to verify that a player has the permission to be able to purchase this order.

Thank you for your time, and your speed in the number of updates on the plugin

I don't think this plugin has any functionality to customize the currency used to purchase items. Economics handles the currency, but I don't think that allows you to use items as currency either.

The permissions available from this plugin are here.

You can customize it with the custom currency option.

Enable it to true and set ServerRewards and Economics to false.
Inside the config set the currency ID to any rust game item ID, the default is scrap. But here you can find a list of all the Game Item ID's that you can set it to. Rust Item ID List

I do support custom items with different skinIDs but not as currency its self with how I am interpreting your question here. 

As far as running custom-created items as commands go I have no way to verify if they have permission to buy, Say a vehicle license.
So instead you should grant the oxide permission for that command that it's calling from the other plugin upon purchase in the multi command string [ ].
This will ensure that they have permission and will get the item from the purchase.