I will only use paypal (or if you're french we can managed differently (ouais j'suis une meuf comme ça, moi héhé!)).
here a exemple of price (for only one character) :
15€ (colored (with detail on the character) with an easy background)
10€ (colored chibi with no BG)
5 € (sketch or lineart (digital or paper....your choice : D))
(It 5€ per adding character (only for the colored one (for sketch and all it's free for only two characters))
If you want to see what I can do (cause I only post my hunger games work here) you can visit my blog : here
And if you have any questions don't hesitate to send me a note ; ) (and sorry for my bad english, I try my best!)