Word to the wise; I might avoid stating outright how much time anything commissioned took you. It puts you at a disadvantage when people look at your prices... they might be like "Why are they charging that much if it only took them 20 minutes? I'm not paying that!" You know what I mean? XD
Try looking up a the Graphic Artist's Guild handbook of Pricing and Ethical Guidelines. Very in depth, covers loooots of different fields of freelance art and design. And it comes out with new editions so it's always up to date!
I'm all unsure on how to do it.
You've chosen wonderful colors to your cupcake