How about this method of pricing...I've been doing wedding cakes for almost 20 years and have made a profit every year, so you can take that for what it's worth.
I know what the average price per serving is around here, so I can't deviate too much from that, but I'm not going to go in on the low end of it, either. I know what my year-to-year gross vs. net is too, after a few years of that being pretty consistent.
Now let's say that I want to make more money than minimum wage. If I know what my net will be, and how much I want to make for the year, I can figure out what my gross needs to be, and then plan pricing accordingly. So for argument's sake let's say that I want to clear around $40,000 for the year and I know that my expenses are about 40% of my gross. That means that I need to earn about $65,000 gross to make that much after expenses. So, considering that wedding season is from about March through October around here, I have about 32-34 weeks to make that. So I should aim for about $1900-2000 worth of business per week. If I only want to do three cakes per week, I need to charge about $600-700 per cake. And if the average servings per cake around here is something like 100-150, I would need to charge somewhere between $4.50-5 per serving.
Now I can go with that, or say forget it, I'm not going to kill myself trying to make that much cake per weekend, and raise the price to $5.50-6. That's on the high end of what people are willing to pay in this area, but it could still work. And of course there are the other 18 weeks that are slower but I can still book business then. So I could leave the prices around $5 per serving and just try to spread the business out throughout the year and not concentrate it all in the 34 weeks of peak season. Or I could hit the jackpot and get a couple of clients who want a huge cake that will be the one project for the week but who will also make the $2000 mark with that one cake. More likely than that is someone who wants a wedding cake, groom's cake, and cookies, like the client I had this week. That adds up, so one client like that can take care of more than the usual percentage of the gross.
Planning prices that way does require that you know what your expenses are going to be, though. Like I said, I've been doing this for a long time so I know what my gross and net tend to be percentage-wise, which helps when figuring it out based on how much you want to take home at the end of the year.
Also, these figures are not the ones that I use, I just chose some that would give nice round numbers ;)