Just a word of advise since you are new.
DON'T give a quote until you've had time to discover your cost of ingredients as well as an estimate of the amount of time it will take you to make it ( 4 hours x $10 per hour and $35 for ingredients = $75 for an 8 in round .
PAY YOURSELF for your time not just ingredients. If you don't, you are paying them to make their cake. I'd just as soon be with my family than in the kitchen working for free.
Then, once you have reached that number, don't back down. If you change your price it looks like either you don't know what your talent is worth or you overcharged to begin with...neither is good for your business.
Remember if a person asks you what you would charge
. That's what they want to know. They are free to do what they want with that information.