I was just wondering what you would charge for a 10 inch cake with 5 baby blocks on top (which will spell out 'twins'), all in cake and all covered in buttercream with some fondant accents?

To cover the cost of my ingredients, time, labor, overheads, and make a profit i would charge $3/serving. You'll need to figure all of these things out though as each of these cost are completely different for each of us and how much i want to make per hour may be very different from what you want to make.

You should charge your cost for the cake (including ingredients, labor, and overhead) plus 20-30%.

and don't forget to include LABOR and OVERHEAD, as jason said, as part of the cost. Too many people on here look at their grocery store receipt and add the 20-30% to that, thinking THAT is their total cost.