can someone tell me how much would you charge for giant 3d cupcake?

I would charge the cost of ingredients plus the cost of labor (with an hourly wage of $10-20 or so depending on the area) plus the overhead costs applied to the order plus a profit margin consistent with local market prices.

I have made several of these cupcakes (you can see a picture of the latest one in my photos). They are very easy to make and rather quick to decorate. But, quite costly to make for such a small cake.

I would suggest you make one and keep track of all your expenses along the way and time yourself. That will give you a starting point because you will know your cost ($$) and time involved (also $$).

depending on the amount of detail and flavor choices, mine are typically $50-$75

I use the chocolate base and after figuring out my cost. I charge $42. It takes a lot of buttercream and it is the smallest size cake I offer. I don't offer a 6 inch single tier cake.

Thank you everyone for your help and reply