So far I did this:

  "Shop - Shop Categories": {
    "Commands": {
      "DisplayName": "Commands",
      "DisplayNameColor": null,
      "Description": "You currently have {0} coins to spend in the commands shop",
      "DescriptionColor": null,
      "Permission": "",
      "Currency": "",
      "CustomCurrencyAllowSellOfUsedItems": true,
      "CustomCurrencyNames": "",
      "CustomCurrencyIDs": -932201673,
      "CustomCurrencySkinIDs": 0,
      "EnabledCategory": true,
      "EnableNPC": true,
      "NPCId": "",
      "NpcIds": [
        "1550427392",
        "7574923776",
        "10534429696"
      ],
      "Items": [
        "Minicopter",
        "Sedan",
        "Airdrop Call"
      ],
      "Command": [
        "spawn minicopter \"buy mini\""
      ]

But It wont work, it wont show the command button, and am not sure if its going to work like that any way :(

I found the problem but now am getting command not found

Merged post
Solved

Got help from solarix over discord!

Here is the solution for any one else who coulnd figure it out like me.

      "Command": [
		"vl.buy MiniCopter $player.id"
      ],