NickCUK on "Add 'Price' field to each photo"

I know I can use the 'Description' field for each photo to add a line for 'Price' but feel this would be better if I could add a Price field to the Database which would display under each photo.

Problem is I have no idea where to start when looking at how to modify ZebPhoto to accommodate this field. I can write PHP but don't want to go modifying core files which should not be touched.

Can someone guide me in the right direction?~

Thanks