I recently got this note:
And unless I'm reading it wrong (which might as well be, since I'm not a native English speaker) they are asking me to design a mascot for a convention (based on a written description they gave me) and use said design to make two badges.
Now, if I am designing a mascot, chances are the design will be reused for merchandise and other such stuff. I doubt the original two images would be used on merch, since they will be traditional media. Now, if my design is to be used to make money, should I charge more for designing the character than I usually do? Should they buy the rights to the design off me, or should I ask for royalties?
On a side note, I already gave them a price offer of ~$30, before I realized I might be dealing with something more than a regular commission. Would it still be okay for me to go back and ask for more, or am I stuck with $30 because thats what I said at first?
I am very new to this kind of stuff, since this is the first time anyone has wanted to commission me for something on a bit of a bigger scale (usually its just drawings of people's OCs or character designs for personal use) so I would like some advice as to what I should do. I don't want to end up getting screwed over, but I also don't want to end up scaring off the commissioner or making unreasonable demands.
EDIT: Here is my dA account so you can get a better feeling of my art and how much you think it would be worth: http://katarrhe.deviantart.com/gallery/
& also my old, abandoned account, which has a lot more of my work up: http://00x181-033-4-9953xx3.deviantart.com/gallery/