Welcome Cakez4Dayz to the CC forums.
There are so many factors which influence the cost of a cake. There are even many different combinations of 3 tier cakes serving 45-201. It's difficult to provide you with a specific answer.
I do wish we had a FAQ which I could link for you. Instead, I will copy and paste a post I wrote concerning pricing:
I'm sure, at some point, this post will get lost in the archives, but it's worth a shot. I really do like to help people. I believe that knowledge is power.
Most of us agree that tossing a number at someone, who asks how to price a cake, does them a disservice. I'm in the teach a man to fish boat so to speak.
Here is my heartfelt and knowledgeable advice. In order to set your pricing, you really do have to do your homework. Sit down & write a list of every single thing your hands touched while making that last cake. Did you use a hand towel? Do you have to wash that towel? Aprons, hand soap, dishwasher, dish soap, oven, water, trash can....EVERY single thing no matter how small it may seem. Of course, you will also add the cost of ingredients. If you are a legal business, you will need to add the cost of licensing and insurance. This should, quite frankly, be a very very long list.
You should also do some research into your competition. Found someone with comparable skills as yours and check to see how much they charge. Don't copy this!! It's possible they are not charging correctly. It will, however, give you valuable information in comparing.
Some people will encourage you that home bakers or Cottage Food Law bakers shouldn't charge the same as a brick & mortar bakery. Really? My question is do you have the same costs? Sure, you don't have the same lease payments. You also don't get the discounts of purchasing power. I'm not saying they equal out. The only way to know is to have an accurate accounting of your true cost.
Remember that the goal is to make a profit. Covering costs does not equate to a successful business. Sure you want to make people happy, you want them to enjoy your cake. As a business, you should also make a profit. We aren't talking price gouging, but you really do deserve to make a profit. Stop feeling guilty about it!
You don't have to have a masters in business, but I do recommend you at least have a business plan. At the very least, educate yourself about the true costs of producing your cake.
Best of luck to you.