Photography commission

So I'm hoping to try and get this concept sketch <da:thumb id="683799942"/> turned into a nice photo to use as potential cover art for the romance novel I've been working on in my down time. It's mostly just a little pet project but I thought it be nice to give it a pretty working cover. The book may see an official publication eventually though I don't know how things will go if that happens. So this may be used in an official capacity but I don't know for sure that a publisher wouldn't just change it. So I'm going to want licencing rights to the image but if you're going to charge me for them please be gentle I've seen artists try to charge hundreds of dollars just for the licencing right to an image that already cost a lost (have bout pinup art or digital paintings)

The cover concept is meant to be the hands of the two main leads, one manicured, clean and tan the other pale and graphite stained. If you wanna get a better idea of the characters and the story you can read some of it here, (mind you it's a work in progress and will probably see plenty more edits and revisions) <da:thumb id="679532045"/>

Now I actually have no idea what the prices are like for photography commissions since I don't know much about the art form. I'm open to see what prices people are willing to offer and gage my pick off of quality and affordability. So I'm looking for a best offer.