minimum wagers?

"In the center of the place...tables were grouped in front of a carsized parquet dance floor...the early crowd made up of construction and service workers and other minimum wagers, shooting pool and quenching their thirst with pitchers of beer."

Is dance floor the area where people dance? Isn't a "carsized" space too small to dance (otherwise I was sure what dacne floor is)? *_*
What are "minimum wagers"? A occupation like construction and service workers? And what is "shooting pool"?

A wager is a bet. It implies that construction and service workers earn low incomes so they place minimum wagers.

In front of the floor space is a gambling area, where the tables are joined up to allow betting to take place.

Shooting pool means playing pool, a game played on a table with lots of colourful balls.

"A wager is a bet. It implies that construction and service workers earn low incomes so they place minimum wagers."

Hmm. That's not how I read the sentence. A minimum wager is a person who makes the national minimum wage (the minimum rate of pay a worker can legally be paid). If read this way, then there is no allusion to gambling in the passage.

In the centre of the room, tables were grouped in front of a car-sized parquetry dance-floor, with an early crowd of construction and service workers and other low-income earners playing pool and quenching their thirst with jugs of beer.

<<construction and service workers and other minimum wagers>>

In this context, "minimum wagers" means minimum wage earners. Although I think construction workers usually make a bit more than that.