Example NBT Input

{
   "offer":{
      "itemKey":"minecraft:dirt",
      "amount":1,
      "priceModifier":0,
      "nbtTags":[
         {
            "nbtName":"test",
            "data":"this is the data",
            "dataType":"string"
         }
      ]
   },
   "request":{
      "itemKey":"minecraft:cobblestone",
      "amount":1,
      "priceModifier":0
   },
   "tradeExp":3,
   "maxUses":10,
   "priceMultiplier":0.1,
   "tradeLevel":1
}