Care to be a part of this?

[Carpaccio]

Hm, since you put it that way, I suppose the payment could be increased for certain things.
I was going on the average rate of comission for artistic design in the fanart world, however. There is research behind my methods, mind you.

How much would you suggest for a sprite sheet?

Remember that a lot is going into this project, such as server hosting fees, and advertising costs, so one must be pinching the pennies at time to support the longevity of a project such as this.