Weddings are celebratory times and for many couples the celebration is not complete without spirits (alcoholic beverages). Consider your guest list as well as your budget when determining the style and type of beverages and/or bar service to offer your guests.
The only real no-no is a cash bar.  This is a party to which you have invited guests.  And if this party were in your home, you would not charge your guests for dinner or beverages.  That said, there are other options to consider when deciding what beverages to serve at your wedding and reduce costs.
*You may choose to host a soft bar.  This includes nonalcoholic refreshments, beer and wine.
*You may host a full open bar for a limited time and then switch to a hosted soft bar.  You may choose to offer house brands of alcohol rather than premium brands.
*You may serve champagne served by circulating while gloved waiters or you may choose sparkling wine instead. 
*For the traditional toast to the new couple, skip providing champagne and simply have quests toast you with whatever they are drinking.
*If you know that your guests are non drinkers or your wedding is in the morning when less alcohol is consumed, you may choose a consumption bar rather than purchasing the site's bar package.  If yours is a luncheon reception a fully stocked bar is unnecessary.  You can choose to serve mimosas, Bloody Marys or other light drinks.  You may elect to have a "signature" non alcoholic drink prepared, or have a juice bar or gourmet coffee bar.
*You may ask the wait staff to only refill glasses when asked, rather than top them off automatically.  You can also ask staff not to clear glasses unless them are empty or have clearly been abandoned.
*Be aware of corkage fees that may be applied when you have chosen to bring in your own liquor.  This is a convenience fee for opening each bottle and also be aware that it may be subject to tax and serving fees.