Refined colored sketch (think; sorta sloppy ink job) probably some basic lighting effects as well : 25-30
Ink+flat color 30+ (+ depends on the details of your character.)
Ink, color, shading, highlights/other lighting gimmicks; 40+ (+ Depends [again] on the detail required for your character)
Prices for colored lines and advanced lighting will vary if you so choose to ask me for it I've only just started dabbling in this. I have not come up with a clear price bracket yet
Add 25-30% per character. This is applied to the most expensive character in the picture if applicable (See bellow)
For example:
2 characters refined colored sketch : 25: i would likely charge something like 35
or
3 characters fully inked, colored, shaded ect: 40 (but lets say one of the characters has some like.. crazy fur pattern and big awkward wings. I'll bump the cost a bit for detail. 45-50~ lets say 50) 40 (+10):2x25% =20 -> 40+20+10 =70
That's 70 for 3 chars at my highest quality output. with wiggle room if the characters are simple.
Prices of background work depends on what you want and how much detail you want. I don’t really have a set price for this but it will scale depending on the amount of detail put into the characters as well. ( It would be a shame to put a lot of effort into a fully inked and shaded picture and end up with a sketchy background. :P )