A wedding is supposed to be a celebration, but increasingly couples are asking their guests to open up their wallets as they sidle up to the bar. Fortunately there are a number of compromises for couples that want to throw a great party but don't want to break the bank on booze (leaving you the cash to buy a beautiful wedding album).
This is the most common compromise brides make with the lushes in their lives. Keeping a bar open all night can dramatically increase the cost of a reception with diminishing returns as the evening wears on. Opening up the bar during cocktail hour lets the free drinks flow in a controlled fashion that's better for the budget and the party mood.
Cocktail hours also have two benefits beyond price.
If you're holding your reception and ceremony at the same venue, a cocktail hour will provide time to change over a room for the reception. Cocktail hour is also a great time to get some formal portraits done (and it's a great incentive for people to get them over quickly).
Beer and Wine Bar
Mixed drinks are called "liquid gold mines"* in the bar trade. They're a potent cocktail of cheap spirits, fillers and high prices that make bar owners swoon. That isn't to say that beer and wine don't suffer a hefty markup, but when planning a wedding couples might consider compromising between the cash bar and an open bar by restricting the open bar to beer and wine.
If you're feeling especially frugal, you can just do an open beer and wine bar like you'd operate a cocktail hour.
Also, I've found that women are more impressed when you actually buy drinks for them rather than simply walk over to the bar and get them. So it's really better for your single friends.
Spike the Punch
You can circumvent the caterer all together and just have everyone bring their own in a brown paper bag. For a hint of nostalgia (great for high school sweethearts), you can simply spike a great big bowl of punch behind the chaperone's back.
*This fact is entirely made up.