Yep - Right now I am going through the images from yesterdays high school senior session. There are over 400 images - at least 100 due to trying to get good images with a less-than-cooperative horse. They will see 35 to 40 tops.

I learned that in the 60's - never show an image you have to explain. Never show one for which you have to make an excuse. Never show more than one of the same thing - and then only the BEST one. My friends thought I was a great photographer - I never shoed them the garbage I shot.

G, make sure your photo gets out there. It's the only way to build a client portfolio if you intend to keep going in that direction.
20k is pretty high if its not going through an agency that reps you. Guys that do that for a living (real pros) may sell one time use for $1-2k. Unlimited use for 6-12 months may go for could be $4-5k. You can sell all your rights for more and you no longer own it. Some factors will be how unique it is. Can they easily get something similar from stock photography. It's all business. If they really want it they may pay a lot but you will never see them again. You want repeat business just like any other clients. Ask them, they may tell you what they feel is fair and develops a relationship and referrals. They are probably small frys and can't pay much. You can develop together. Big companies go through agencies and they do it all for you. They expect you to keep shooting and sending stuff they can sell.
My info is based on a few guys I know that make their living doing that. They have agencies that rep them. Good luck.