Is it buttercream or fondant? What flavors/fillings?
You should charge $0 if your area will not allow you to sell cakes.
If you can sell, then you need to figure out how much it costs you to make your cake and add that to the amount of money you wish to be compensated for your time. That would be the ideal way to charge.
I am only a hobbiest, but there are many, many posts on here about pricing. It depends on your skill level for one thing. You need to know how much you have invested in the ingredients and other expenses such as electricity, boards, boxes, etc. If you haven't already, you should check with your state to see if home bakers are allowed to sell baked goods and if so, go thru the paperwork of becoming legal. If you do a search regarding pricing you should come up with lots and lots of answers to your question.
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