How to I approach a difficult payment for services issue with a sibling?

I started a small business building websites. My sibling asked me to build one for her husband and within 48 hours, I had it built. They absolutely loved it and thanked me numerous times. I told them that my average price is $100 page (which I was fibbing about because it's much higher) and that I would give them a discount. I felt awkward discussing it with her since she is a family member so I just told her I'd leave it up to her to decide what it was worth. I got a check for $30 in the mail today and I am just livid. I realize I should have been more courageous and asked her for a specific amount but I NEVER expected this. It's a total slap in the face and I spent about 20 hours in 2 days building it. Any suggestions besides never talking to her again?

Did I mention they're loaded? Maybe this is why...they're cheap (UGH)!!!!

Be glad that she at least paid you something. If you want to be mad at someone, be mad at yourself. You had the chance to set the price and failed to do so

You learn from it and never expect from family what you would expect from a total stranger.

Family seems to think they are entitled to ore for less because it is family.

This makes me mad too! You have to do something! I understand it, my sister is a little bit like that but she has her history, she never appreciates what I do for her, and she makes me feel that I don't do enough for her. I love her too much, and she takes advantage. But one fine day, I gave her a piece of my mind. She stop talking to me for four months and she came back more loving.

Put your foot down on this one or be the mat for her.

Mabe she doesnt really know the cost of that type of work ! I would have never guessed it would take that many hours or what the price would be ? She is your sister, be honest an