Please remember that the estimates you are reading depend heavily on the location. A wedding in NYC costs more than some small town in the midwest.
We spent approx. 20k of my In-law's money. Afterwards they let us keep the remainder fo the budget. Had we known this was the deal we would have eloped and kept the cash.
We had a very informal wedding--cocktail party, brief civil ceremony, dinner and dancing. Not quite 100 people. Mid-Atlantic region of the US.
Now that it's years past, my wife says we should have walked to the court house and fogotten all the hoopla, no matter the money. It was actually something I advocated for at the beginning. Whatever. We had fun.
If it were my cash, I'd go the local justice of the peace and pay the court fee. Invite your family and friends, then head out to a nice restaurant. Spend the money on your honeymoon and a house.
Whatever you do about the budget, do not hassle her on the price of her dress. Whatever she gets is perfect--do not dream of uttering a word to the contrary.