It would be an incredibly useful feature if you could add chat commands for purchase rather than only console commands. some console commands are bound to the server console and not client console. because of this some plugins like tank commander are incompatible with GUI Shop in regards to sales and configuration.

It has chat commands. What exactly are you looking for? In most cases, a console command is runnable via the F1 console, unless the Rust client has an existing client-side command that would conflict with it. Console commands sent to the server from the F1 console on a client are handled by the server and/or plugins accordingly.

spawntank 1039 1 -1161 ## this works in server console
spawntank ################# ## this works in server console

this dose not work in F1 console
I'm guessing the word spawn maybe conflicting?

if "/spawntake" could be used that would be great.

this is as far as I've been able to get. pic of shop If I try to purchase a message is returned "item is missing from shop", perhaps I'm missing something.

    "commands": {
      "description": "You currently have {0} coins to spend in the commands shop",
      "name": "commands",
      "buy": [
	  "tank"
	  ],
      "sell": [],
      "npc": false,
      "npcID": null
    }
  },
  "Shop - Shop Categories": {
    "tank": {
      "item": "spawntank",
      "img": "https://i.imgur.com/yB5NEg2.png",
      "buyCooldown": 0,
      "sellCooldown": 0,
      "sell": 1.0,
      "buy": 1.0,
      "Fixed": false,
      "cmd": null​

update I just tried using heli control I figured why not try something that already has outline configuration.

      "cmd": ["callheli pos \"$player.x $player.y $player.z\ 1""] 

GUIShop v1.7.0: Failed to load config file (is the config file corrupt?) (Bad JSON escape sequence: \ . Path '['Shop - Shop Categories'].heli.cmd', line 1477, position 61.)
GUIShop v1.7.0: Failed to load config file (is the config file corrupt?) (Bad JSON escape sequence: \ . Path '['Shop - Shop Categories'].heli.cmd', line 1477, position 61.)

      "cmd": ["callheli pos /"$player.x $player.y $player.z/ 1""]

GUIShop v1.7.0: Failed to load config file (is the config file corrupt?) (After parsing a value an unexpected character was encountered: $. Path '['Shop - Shop Categories'].heli.cmd[0]', line 1477, position 30.)
GUIShop v1.7.0: Failed to load config file (is the config file corrupt?) (After parsing a value an unexpected character was encountered: $. Path '['Shop - Shop Categories'].heli.cmd[0]', line 1477, position 30.)

everytime I think I'm correcting an error a new one pops up. 
at this point I am absolutely confused on how to configure this.
I checked multiple forms and discords and others are just as confused.

Merged post

I got some help from Rust edit discord this is how.

    "commands": {
      "description": "You currently have {0} coins to spend in the commands shop",
      "name": "commands",
      "buy": [
	  "tank"
	  ],
      "sell": [],
      "npc": false,
      "npcID": null
    }
  },
  "Shop - Shop Categories": {
    "tank": {
      "item": "",
      "img": "https://i.imgur.com/IlfCsk7.jpg",
      "buyCooldown": 0,
      "sellCooldown": 0,
      "sell": 1.0,
      "buy": 1.0,
      "Fixed": false,
      "cmd": ["spawntank $player.id"],
    },

"callheli pos \"$player.x $player.y $player.z\" 1"

You had the 1 before the quotes which was your issue...