Not too difficult to
Not too difficult to determine the cost of firing your kiln. Here is one of many links that turn up if you “google”:
As far as decorating goes, if you are doing this because you are a good friend, then charge for supplies (or if you’re feeling generous, don’t charge). If you plan to make this a side business, then you need to charge for kiln time, materials, your time, overhead, etc., and also take into consideration that many people do such things for income, and if you price your items too cheaply, you’ll be undercutting someone who’s trying to pay for supper.
Jester’s Baubles Fused Glass Designs