Family and friends (of family) should be willing to pay the going rate, not to expect a discount.
After all, as a "friend" they'll be expecting a top job. Why should it be then be cheaper?
The worst offenders in my experience are people with non-jobs like middle managers or the legal profession, by that I mean people who actually make, produce or contribute absolutely NOTHING to society - they just suckle at the corporate teat.
These kinds have no understanding that our TIME as a tradesman is the most valuable thing that we have.
My mate's rate is completely free (when I can find the time - i.e. not very often at all)
Other than that, they can pay like everyone else and get an A1 job with a little bit more sparkle - coz we're friends.