I remember asking my friends what they thought of attending a wedding without an open bar. I got a lot of pensive looks, followed by, "Well, an open bar would be nice." I should also add that the friends I asked, like to drink... a lot.
Of course we decided to go with an open bar for three hours. While we didn't get the top-shelf goods, we ended up extending the open bar an hour for a whopping $500 because everyone was having such a good time.
I’ve attended plenty of weddings where only beer and wine were available (much cheaper option, and less drunks to deal with), and in all honesty, no one really cares.
If you want an open bar, head to Costco and stock up. Of course this would only work if you chose a private location for your venue. To keep costs at its lowest, you can have a dry wedding (no alcohol at all), or have guests pay for their own drinks.
Total cost: $3,000