What are your ingredient costs and how much/long will it take you to make? Once you figure out costs and an hourly rate you will be able to figure out how much to charge.
I would pay $130-$150 for the cake.
ANobody can just give you a number, that's not how it works.
You have to work out how much you're spending on supplies and overhead, then work out how long it will take you and decide what you think your time is worth (at least minimum wage), then come up with a number that covers that and keeps you in line with your local market.
If you're just making it for a friend then you have to decide for yourself whether you should charge enough to make a profit or just enough to cover your costs. Only you know what you're willing to accept and what your friend is willing to pay.
If you're doing this as a business you need to make a business plan asap that covers this kind of thing.
AVery well written Kikiandkyle!
AI have been wondering the same thing. I just know about how much everything cost and my time. Fondant always makes the price go up. Kikiandkyle said it the best!
AI didn't mention legalities in there but since the OP mentioned mud cake I assumed they were in Aus and I don't know about their laws.
It's important to check whether you can even legally sell cakes, even just to friends, some jurisdictions will say its fine, some say charging just for ingredients is a no-no, some will allow you to run a business from home with no legal issues. You may also need to get liability insurance if you're selling cakes, even if its just to 'friends'. Most of the time, illegal bakers are turned in or sued by 'family and friends'.