Obviously if your company and their client want to use your pictures, they are pretty good, so experience has nothing to do with it...It also sounds that by giving you credit for the photos, they have already pay you off, so be careful with the generosity...as far as price is concern, if this is a one time deal and is for giving away not to make a profit, you can easily charge them the same that they would pay on a stockphoto site... $10/$15 each sounds like a fair price.