A good friend of mine is planning a weekend away for a milestone birthday going to a specific place to do a specific thing. She mentioned it about a year ago and I wanted to go, looked into how much it would cost and budgeted accordingly. She has now found a tour to do exactly what she wants to do, it sounds lovely but is almost twice my original budget. I've said that I will only go for 2 days rather than 3 but she has said that she really wants me to go and has offered to pay the difference. Although we are good friends this just doesn't seem right, its a lot of money BUT I think if I don't go then she might not go and I really don't want to ruin her weekend. WWYD, accept the money or bow out?