Hey, I was wondering if some Dopers could help me out with this. I recently met a couple of guys from a startup toy company - whom I can only hope are not also Dopers 
- who are interested in having me sketch concept/costume ideas for their figures (presumably on a part-time/contract basis). They want to meet with me at some point soon to discuss duties and rates. I’d like to take this on, it’d look good on my resume and sounds like cool work.
I’ve been doing this kind of stuff for a long time, but never officially, for a company, and I have absolutely no idea what a normal rate is. Anyone work in design like this or remember a similar thread they could point me towards?
My wife has some friends in that line of work, so I’ll ask her tonight if she has anything to add. I would say your biggest bargaining point shouldn’t be about money upfront, it should be about future profits. Try to get yourself a piece of the company, such as a percentage of the income generated by the sale of the toys you are designing for. Be prepared for them to balk at that idea, but it’s probably a good place to start as it shows your confidence in what they’re doing, and that you would like to be considered part of the team.
Regarding a flat fee, it’s hard to say without knowing more about the company. Just remember, you don’t want to end up in a situation where you were paid $500.00 flat fee to design the clothing on the next Cabbage Patch Doll (or whatever the current ‘must have’ toy is).
And, no matter what happens, get your agreement in writing and keep copies.
Thanks for the advice and links, guys 
I think that meeting is coming up, and I’m starting to feel better prepared!