So the way that it works is when you kill a mob it will give you some money now. you can find the total money you have by doing /balance . if you want to spend it in the new shop it won't take up your inventory. if you still have dem evil credits just do /convert and it will become money. also if you need to pay a user just do /pay xNebulastarx 1000. that is pretty much all you need to know!