AITA for telling my BIL to pay me $3000 to pay for his wedding or leave me and my wife alone

So my sister and her long term boyfriend (3 years) are getting married in 2 months and I was going to be best man. They were originally going to have the wedding in June 2024 with our parents paying for it, but now they want to have the wedding this year in August 2023 and are saying they only need 2 more months to save.<br><br>I said that's fine but I'm not going to pay for any of this and then my BIL asked me how much I need. I said that I want $3000. He said that's exhorbitant and that he was only thinking of $500.<br><br>I said $500 is not enough and I said that I want the money by this weekend. My sister called me and yelled at me and said that I'm being selfish and that this is her one day and she can't do it without me. I said that she can get a different best man and she said that she wants me.<br><br>I said that I want the money by this weekend or I won't be attending.