Do you think $75 is unreasonable for a baby rump cake to feed 25 people? It's just like the one in all the pictures on here. The cake was going to be iced in buttercream and the rump was of course being covered in fondant.
I always cahrge $2.50 a serving and depending on the amount of detail and fondant included, it goes up from there. I ALWAYS deliver the cakes so I think that I am very reasonable!! I am in Alabama by the way.
As you are going into business, depending on the laws of your area, you have to take into consideration the cost of doing business. This includes your insurance, any kitchen rental fee, supplies as well as how many hours you think it will take to make and decorate the cake you are selling. Top that off with what your local market will bear in price. From there you will be able to figure out a base price as well as figure out what additional decorating costs will add to that cost. Then you will be able to set your price. In my area I get $4 starting price for a 3D cake such as that but in your part of the world that may just price you right out of the market. I, however, have insurance costs as well as kitchen rental costs to worry about in order to make any money so that is what I charge and it also happens to be in line with other area cake artists. You will have to do a little math to figure out what will work for you price wise in order to know what to charge.