TV show is asking to use a photo, what now?

They're banking on the hope that your desire to have one of your images used in their production (or maybe in the promotion of their production, you haven't exactly made that clear) will overcome your desire to be paid decently for your work.

If you ask more than a pittance they'll probably find another way to get an image of the actor that will work for their required usage. If the value of your image to them is that it was taken when the actor was nine years younger than that actor is now, they'll keep looking for other older photos of the actor until they get one that won't cost them much of anything. If no such other photos are forthcoming, they'll try to create something by using makeup to make the actor look like their younger self, or find a younger doppelganger that can be made up to look like they could be a younger version of the actor, or anything else that would be cheaper than paying whatever your stated fee to use your image would be. Only when your fee (or lack thereof) is their cheapest option will they be very likely to use it.

So the question is whether or not you'd rather give away your work so you can see it used in the production or if you'd rather not give it away and let them use something else instead. Only you can answer that.

The National Union of Journalists has a good freelance fees guide for photography. Note the fees are in £GBP.

Try also checking rates at Gettyimages if you want another reference. In my experience, licensing agents -or any buyer for that matter- rarely offer a budget, so I ask for the desired usage rights required first, work out a price I feel happy with, then send an estimate.

All the Best, hope that helps.