I went through this exact same thing with my longest LTR. We were pretty serious and talked often about the future (house, kids) I really loved her. Everything seemed to be going great.
We attended a friends wedding one day and it was a REALLY expensive affair (his folks spent almost $200,000 which I think is ridiculous but whatever) Of course she absolutely loved it and started gushing how it was the perfect wedding, etc etc. The bride's engagement ring was 4k btw, looked a lot like this:
http://www.weddingjewelry4u.com/images/silver-vintage-cushion-diamond-engagement-ring-p2795.jpg
Right then I knew there were going to be problems but we just enjoyed the day and went on with our lives. Two, count them,
TWO months later my friend is getting a divorce. They had both been cheating on each other for years apparently, yet saw no problem with blowing a huge chunk of his life savings on that stupid wedding. F*ckin morons.
Anyways the subject of money came up again and my girl said it didn't matter if they broke up because the wedding is the bride's "special day" and no one could take that away from her. I tried to reason with her, pointing out the fact that these folks could have bought a freaking house AND a car with that money instead of renting the sh*thole they live in but she seemed pretty adamant. Things just went downhill from there.
She came out of pocket and said that she didn't want no cheapskate husband and if I wanted to move forward with our plans I'd have to "put a ring on it", and a heavy one at that. At the time we were both pretty poor so this whole thing seemed like some Twilight Zone sh*t. I asked her a simple question:
Ok then - what sacrifices are YOU willing to make to be with me?
She looked at me like I was crazy, then gave me the usual BS speech about taking care of me, loving me etc. I told her
"No, that's something you already do. What specifically can you do for me that is comparable to months or even years of hard work to pay for a ceremony and a trinket that you really don't need other than to impress your friends?"
As you can guess this deteriorated into a full-blown conflict. I let her know that I didn't want someone so materialistic and superficial with f*cked up priorities by my side. She let me know that she basically wanted a sugar daddy. We broke up that same day and didn't speak for years.
Last time we saw each other she had indeed found her sugar daddy, this Papa's boy whose family owned several restaurants and a hotel in the city. She had everything she wanted, the extravagant wedding, 6K on her finger (one 4k rock with two 1Ks as neighbors, kind of resembling male genitalia strangely enough). And guess what? She was already cheating on him - in fact she came onto me wanting to have a "go" for old time's sake. I was far too disgusted to even think of it.
Right then I decided two things:
1. I will probably never get married. It's just a huge, meaningless waste of an institution engineered to seriously f*ck a man over, and holds absolutely no guarantee other than people's "word" which is practically worthless nowadays
2. If I ever did get hitched, the girl I chose would care more about me than material bullsh*t. Plain and simple.
As far as I'm concerned your girl has waved a HUGE red flag, and is showing you the type of entitlement bullsh*t you will probably have to deal with for the rest of your life should you choose to get locked down.
Just a heads up from someone who's been there. Be smart about who you choose as a life partner. They should hold the same core values that you do or you will be in for a world of hurt and misery down the line.