The punishment for a misdemeanor depends on the circumstances and class of misdemeanor of which you are charged.

For example if you get caught with a bag of weed that has more than 25 grams of pot, that is a Class B misdemeanor. Technically you could do 90 days in a 'pound you in the ass' correctional facility like Riker's Island. More than two ounces is a Class A misdemeanor which could bring one year in jail.

First time offenders normally wouldn't go to jail. They would be fined and something like community service would be negotiated.

The guy smoking a joint on the park bench would pay a fine and quite possibly have his case adjourned and if he stayed out of trouble for a year the case would be dismissed.

Large amounts of pot possession are felonies.