I would say look around. It really depends on the quality of pics you are going to produce. This may not be the right site to get a good honest answer out of someone (hence the GFY), but I have seen exclusive photos go from $2 per image to $10 an image (just personal experience, could be higher or lower).
I think you need to get a feel for the market, produce a set and see what you can sell it for as a test, or maybe talk to another content provider to see if they will give you some advice.
And don't take offense to people asking to see her tits, or wanting to ride her....it is the porn industry ya know
Andy