That’s entirely up to you. Some hosts like to set up quite the spread, while others keep it as simple as a few bowls of chips. You can always let your guests know if there will be drinks or if they should bring their own (BYOB - Bring your own bottle). Whichever you go for, make sure you include this information in the concert details. 

TIP: Unless you have a license to serve alcohol, you should NOT set up a paid bar.