How much to charge for recital portraits?

[newbie builder]

I've been asked to shoot some portraits (some headshots, some full length too probably) of a young violinist who needs portraits done for promotional use--flyers, etc advertising performances. So, she basically wants a session (probably about an hour) at the location of her choice (tbd) and unlimited use of the final files. Any thoughts? I started to think of ballpark figures, but I realized I didn't want to grossly undercut the competition or overprice myself, so I'd ask here first.

Thanks!