Charging Stations

I just picked up my first EV yesterday and have questions about charging stations. I know some are free and some are paid. However, If I pull in to a charging station that charges say $1.50 an hour and I am gone for 5 hours to work, am I going to be charged $7.50 total? Do I stop being charged when the battery is at 100%? And can you leave your car plugged in while at work or is that bad manners to tie up the space all that time?
Thanks for any help from this newbie.