Wanting your guests to drink and be merry may take a huge chunk out of your budget. When choosing a bar, there are several things to consider. For example, how many guests are you having? What type of reception will you have? What time will it take place?
Look at your guest list--how many "drinkers" are there? What kind are they--the occasional glass of wine with dinner or the top shelf connoisseur?
You have several choices:
1. Open Bar
2. Limited Bar
3. Juice, Soda and Coffee bar
And within those choices are several other options you could use to personalize your event.
With an open bar, the possibilities are endless. Sadly, the same could be said about the bar tab at the end of the night. You could choose to limit your bar instead, in whichever way you deem fit.
Opting for a limited bar allows your guests to choose from a selection that you have chosen with your caterer. Is it necessary to have brand liquor? Are mixed drinks a non-negotiable? With this option, you can choose what alcohol is in your bar. If you have a hard time saying no to people, you could let someone do it for you. You could have an extensive selection of alcohol but "limit" guests to a certain number of drinks. I always recommend the former, as the latter may cause some disdain during your fête.
You could also limit the times that your bar(s) are open. For example, keep your bar open during the cocktail hour, dinner and the toast. During your cocktail hour, have extra waiters pass drinks on trays instead of guests going to the bar. This will lower consumption among the guests. Shut down your bar early in the evening to not only save money but overconsumption and driving.
If your caterer is agreeable, check into bringing your liquor. While you may get hit with the inevitable "corking fee", but the advantages are that not only can you shop around for the least expensive prices, but you can return the unused bottles for a refund or keep them for yourselves.
Another thing that I absolutely love at weddings is the "Signature Drink". Take into consideration your overall theme--it's colors, its meaning, etc. Have a drink that is a culmination of all those things. For example, if yours is a country wedding, fully equipped apples and gingham, make yours a green apple sour with real apple slices. Perhaps it is a tropical wedding--serve Blue Hawaiians garnished with fresh pineapple and rimmed with coconut. Look for great combinations at sites like http://www.idrink.com. With the money you save from only serving the alcohol used to make your drink, you will have enough to rent opulent glasses for the first round.
Whatever you do, avoid going the cash bar route. You risk offending your guests by having one. Typically, guests do not bring cash to weddings, and why should they? They just spent money on travel, clothes and a gift! They are there to celebrate with you. Asking them to pay for drinks is like them sending your wedding present C.O.D. Avoid it at all costs.