I have altered clothes for years and sold various crafts and am a free lance Home Economist/Consultant- all work where I set my own prices.
This is my best advice- esp since this customer is NOT IMMEDIATE family, really she isn't. Charge more -think of what you would or have paid and charge at least that. I believe when you cheapen yourself and your skills you send a message to others and yourself that you are not worth it. Set a good price, a fair price but do not discount yourself. Tell the customer your price and make no apologies. If you are questioned, the answer is "frankly I am committed to great work and charge a price that makes me be able to devote the time and effort to give you the wonderful results you have a right to expect." IMHO It is better to lose those customers that want too low prices and get paid for the quality work you do.This family discount - and lets face it she is much removed- phooey- creates a bunch of extra layers. Are you going to keep doing more at a discount, even when it eats into your family, personal time?? Would she discount for you? How much are your lives entwined?
I also stress that I do not alter for just anyone- this is true- it weeds out bargain hunters that do not respect your skill and time and also creates a feeling of exclusivity. I only take referrals-keeps the payment problems down. This philosophy has worked for me- I can not handle all the work I am offered.
Do not cheapen or discount your talents! We women tend to do that, I believe because of the fact that so much of our life/family work we are not monetarily compensated or recognized for.
Now I relinquish my soap box to someone else...