My best images are on Flickr and I've had interest in some of my cycling photos (Tour de France, track worlds, etc). On a couple of occasions I've given the riders free usage of the photos if it's for their personal website.
A few months ago I had a rider's manager contact me about using a photo in the brochure and point of sale materials for his client's sunglasses sponsor. They weren't prepared to pay anywhere near a suitable fee for that kind of usage - essentially they wanted it for free, if they could. They're not using my photo.