Why the argument over a cash bar???

As an adult, YOU made the choice to get married and have a large guest list along with providing a meal for those guests. I am sorry but if you cannot afford everything that you want that does not mean your guests should be obligated to fork over the dough. People come to celebrate your nuptials, not just a free meal and alcohol. If that is all you think of your guests, why are you even bothering at all?