Do they sell beer during concerts?

It has to be a public approved concert where the street is closed down. If monument street isn't closed than they don't sell beer

Some events do, some dont

Some events have vendors but there are multiple bars in the area.

No

During some events there are vendors that sell beer and wine. Normally it requires ticket purchases from one booth then going to the alcohol truck or booth afterwards to get your drink. Be aware they usually start at $3.50 per beer and go up from there.