Who here has a licensed their photos out before?

I do mostly video work that does not extend beyond the client that hired me.

A few months ago I was hired to cover the grand opening of a local New car dealership. Provided the footage that I was contracted to provide, and while they're snapped a couple dozen still pictures. Some of which were of some race cars that were on display.

Fast forward to this afternoon and I get an email from the race team wanting to license three of the photographs. I have not spoke with him yet so I do not know what the purpose for them is going to be but my best guess is for their website and some marketing material.

I do not know what to charge them for the three photographs, I know they're really unique and good photographs and I have an idea of the three they want. I just don't want to come in to low or too high when I give them a price.

Any advice, experience and information would be greatly appreciated