This isn't normally something couples spend a whole lot of time discussing when planning the wedding. Usually it's decided quickly or handed off to someone else. But, I encourage you to spend some time considering what drinks you want to provide for your guests at your wedding! Not only for cost purposes, but for the style of wedding and the party you actually want to provide.
When looking at cost, you may have the option to offer an open bar or a cash bar - or to purchase a package through your caterer that covers a certain selection of drinks. You may be able to bring in your own alcohol, or you may have to use what the caterer can get. That really depends on who has the ABC license. You may have to pay an uncorking fee if you bring in your own drinks, which may end up costing more than just using what the caterer can get.
But, I'd rather focus on the style of party you're throwing for your reception than the cost of alcohol. If you're a party-all-night, out-on-the-town couple, it would make sense for you to offer a full bar and have a variety of choices, so you can throw a party your guests will never forget (though they might struggle to remember how they got home!)
If you're the couple that enjoys a glass of wine or bottle of beer when you get home from work, or enjoy going to wineries and breweries together, it might be a good idea to select a few special wines and beers to share with your guests that you've enjoyed together.
Or if you don't care what you have at your reception but just want everyone to have fun, pick a couple options for each type of alcohol - but don't stress it.
It's becoming more and more popular to offer a speciality drink or two that represents you as a couple, which can be a great way to offer a mixed drink without having to offer an entirely stocked bar. For us, we wanted Starr Hill's "The Love" as our wedding beer, and we had a limited stock available at the wedding. Even though it ran out so fast, it is still what people ask us about!!
I would caution all of my couples to consider what type of event they want to have when they select what their bar will be. Offering liquor invariably makes an event more lively, which can be fun but isn't always a great thing. It's important to take into account your guests, your habits, and what you want people to remember from your wedding. So, those are my thoughts on what alcohol to serve at your wedding! Make sure you talk with your soon to be spouse about your desires and plans, and go from there!