How much would you charge??

This site has people from all over the world. Therefore, pricing is not something anyone can really help you with. You may want to check on other bakers in your area because cost of ingredients vary so much from place to place. My advise would be to figure out the cost of everything and I mean everything you will need to make this. Estimate how long it will take you to shop, bake, clean up and decorate to determine how much to charge for labor.

I agree with Goreti.
Ingredients, plus time and materials (also remember gas and electric needed to bake and decorate), then work out travel if delivery required and add profit on top at whatever percentage you feel you can charge.