I charge a flat rate of $50 per hour for my work. I charge in increments of 15 minutes (rounded up) but my minimum charge is one half hour or $25 even if you only need ten minutes of my time. Obviously, I'll be happy to stay and do whatever else I can for the rest of the half hour you're paying for in a situation like that.
Because I have a regular job, I can only do this work on evenings and weekends. I travel routes 3, 495, and 290 between Nashua and Worcester. If we can arrange things so that I do the work for you while I'm passing through, I can minimize or possibly eliminate any charge for mileage. Specifically, if you live within three miles of the highway and I meet you on my way home from work, I won't charge you anything for mileage. If you live more than three miles away from my route, I charge 37 cents per additional mile. If you need me to drive to Chelmsford on a weekend (when I wouldn't normally be driving past), I'll have to charge you for the entire distance from Nashua to Chelmsford (minus the three miles that I include free).
There's no charge for the time spent setting up a meeting, of course. On the other hand, if we set up a meeting but then you ask me to find out what kind of RAM you need for your computer, I'll charge you for the time I spend doing the research (I'll remind you before doing so, though). Please feel free to ask me for additional pricing details or estimates any time.