You could always just ask him what it pays and give him your rate. Lead with the assumption that it's a paying gig. If he's looking for free content you'll find out right away, or never hear from him again. I can see why he'd want to feature some of your photos, standing alone they are very good examples of street style, especially that wonderful shot of the skaters. Looking at your whole body of work makes it obvious that you're not a typical street guy, but those few images stand on their own very well.