
I don't know what your parent's financial situation is like, but my dad is around the same age and if he wanted to buy his "dream car" and refurb it, he would just do it. It would give him something to do, keep him busy.
I went through similar situation recently (albeit not as much money). I threw my SIL a VERY NICE baby shower that cost me several hundred dollars (about). However, I planned it over several months and budgeted for it. It was something I really wanted to do for her b/c she has watched my two girls many many times and has never asked for or accepted a dime from me. She watched them a couple of times when my husband and I needed a weekend away and she has always been available at the drop of a hat. She totally deserved it and that was my gift to her. So a couple of weeks before the shower, my SIL #2 asks me what I am getting SIL #1 for a gift! Hello!!! The shower!

She's like "oh, I was getting her the crib she wanted and I was hoping to split it with you". I was like, uh no.
I am also going through another situation right now (again w/ SIL #2). She lives in another part of the country and flies to FL several times a year w/ her two kids (she's a SAHM) to visit us and rest of the family. She gets offended when we don't come up to visit her. She doesn't understand that we have jobs, limited time off, and money is tight. She puts everything (I mean everything) on a credit card, therefore getting herself deeper and deeper into debt.

So when she wants to fly down, out comes the plastic.
Problem is, her DD (my niece) is turning 7 next year and she promised to take her to American Girl Place in NY to get her a "big" doll. They live not far from the city, so it's only a train ride there for them. She really wants me and my DD to come up there to visit and spend a few days in the city w/ them. I just don't think we can afford it. My DH is going to Vegas in December for a "boys trip" that we have been saving up for. Plus we are doing
DCL next September. Our credit cards have been completely paid off

and we refuse to put anything else on them. Our new motto is "if we can't pay for it w/ cash, then we can't afford it". So we are doing a lot of saving, etc. I know that SIL will be pissed knowing that we are doing DCL, but it is very important to us to have these family vacations as we don't get a lot of time together anyways due to crazy work schedules and such. We value these vacations and weekend getaways (to Disney, of course) w/ each other. I haven't told her yet and I know she will be mad.

She will probably offer to pay for it but I refuse to be treated like a charity case. Especially knowing that I would be contributing to her deepening debt.
Sorry to the OP for completely and totally hijacking your thread, but when I start ranting, it just keeps going!

I would just tell your sister that you can't afford it. That's all that you can do at this point. If she gets mad, then let her worry about it. Your parents would hopefully understand why you can't fork over that money. Gosh, sounds like I should take my own advice, huh?
