Good afternoon ...
In stock photography, the price is determined by the resolution (in pixels) and size (MB).
There are generally four sizes: Low (Web 250 x 500 or less)- Medium (1000 x 2000) - High (2000 x 3000) - Ultrahigh (3000 x 4000) with prices of very roughly $100, $200, $300, $400 and up for royalty free (RF) ... you grant unlimited use forever, but you can sell to more than one buyer under those term. There are other stock sites that sell an image for $1 but I wouldn't go there. I also believe there is a bit of negotiating downward after an individual expresses interest.
If the buyer wants exclusivity for a period of time (at least a year) the sky is literally and figuratively the limit, which is determined by type of use, commercial, advertising, product. This type of arrangement is called Managed Right (MR) and you can negotiate to retain a limited right to use.
Just so you know ... I learned this while considering selling my photography as stock (I didn't). I also have some excellent sport photographyn that I need personal/individual releases in order to sell so I am going to offer a RM license to the athlete in exchange for a individual release with limited edition of prints.
Also, I wrote this from the top of my head ... I can doublecheck figures and facts if needed.
--
Len
"Nobody goes there anymore ... it's too crowded."
--- Lawrence Peter "Yogi" Berra, #8
"The secret of managing is keeping the guys who hate you away from the guys who are undecided."
"You could look it up"
--- Charles Dillon "Casey" Stengel, "The Old Perfesser", #37