The usual selling point is that the bars are temples. But the pearls ain’t free.
A goodly number of them, I’ll clue ya. 
As for dive bars and music, sure they can have live bands. The diviest bar where I grew up in West Texas, possibly the diviest bar I’ve ever personally seen, often had music on weekends. Some other dive bars too. In fact, the band that played most often in that diviest of dive bars, the musicians were all regulars of the bar themselves.
Is the bartender drunk? drinking? or at the very least likely to have been more than one day this week while on duty?
there’s your first hint you are in a dive bar.
Not sure about that. I’ve had plenty of drinks with bartenders at “nice” bars.
Pull-tab lottery ticket machine. Plastic ‘mugs’ that look like glass, but when you try to hoist it for the first time you about throw your beer in your face. No tips on the pool cues.
The one where you don’t make eye contact with the Greek sailors, the piss on the floor in the ladies room is almost ankle deep, the stalls are missing their doors, and the girl on the toilet with the needle in her arm says go ahead and pee honey, nobody’s gonna watch.