I used to, but it was a lot to keep up with. Now I have one set price and serving size. I charge a per serving price, and then charge based on the number of hours of “art time” I will have in the cake. I do charge extra for fondant also. I think my customers (at least) like a simpler price structure.
Its easiest to work out how much per hour you would like to earn – keep a record of the time spent including any shopping baking time and clearing the kitchen time and work out now many hours you have spent. By adding on the ingredients and any profit you wish to make – this method means that you are rewarded properly for your time. Over time a pattern emerges as to the ‘normal’ price for a cake. In UK we do not tend to charge per slice – but normally a wedding cake would be way more than a party cake – mainly because of the fruit and marzipan involved (or the stress levels involved in a three tier fresh cake to be made only 2 days before the wedding!)
I am just working on a matrix which works out from your store cupboard purchases the value of your requirements for a recipe which is simple and easy to use – we are just checking that it makes sense. It will work out the value of ingredients and boxes and boards etc, and it is simple to add in the value of your time. Each costing can be labelled if desired and printed out and kept on file for quick reference. Will let you know as soon as its done!