Who plans a Bachelorette party for a monday-tuesday? Odd. If it was me I would go to everything, but decline the hotel, due to working. I think spending 300 is a reasonable amount for dinner and a winery and it sounds like you can afford it so think you should go instead of saving for a vacation with your sister even though that is what you'd rather do. As a pp stated agreeing to be in a wedding comes with lots of expenses most would rather spend elsewhere, but IMO that is part of saying yes. If they were asking people to spend a ridiculous amount it would be one thing, but a nice dinner and night out is easily a couple hundred plus the tradition that everyone chips in for the bride, the 300 seems reasonable and if you don't stay at the hotel I'd guess it is closer to 250 for you.