Shakespeare's audience was very mixed. The nobility came, but so did the "groundlings," as they were called.

The poorest would have stood, not sat, and would have brought cheap (and probably smelly) food with them. If they didn't like the plays, they would have tossed it at the stage.

As far as we know, people went because they liked it. You might think of it this way. Relatively few people could read (probably no more than half), and books would be very expensive. There were no movies, and no recorded music. Except for other period entertainments like bear baiting, the theater was it.