I don't charge at all for sewing. I do it for free or I don't do it. I have sewn for money in the past and I've found that no amount of money is worth my time when it comes to sewing. That's just me though.
That said, I have paid skilled seamstresses $10-15 per hour for contract sewing, i.e. my pattern, my fabric, my thread, multiples of the same item. I prefer to work it out to a per piece cost.
For advertising design I don't charge friends or family. And I try not to do work for friends or family at all, just give them advice and point them in a colleague's direction unless it is something I can do fast. Professionally I used to charge somewhere along the lines of $50-$75 per hour depending on the type of design and other factors. Most of my colleagues would consider this cheap in my field. Production artists might be paid somewhere in the $25-35? range for their time, somewhat analogous to contract sewing.
I have no idea what fashion design is worth but you might get some ideas from Kathleen Fasanella at
www.fashion-incubator.com. She has an interesting book on the fashion industry if you can borrow it from the library or pick up a used copy, it's not cheap. i imagine there are similar differences between production sewing rates and rates for custom sewing, and design/pattern drafting rates as there is in the field of advertising design.