Some use quarters and some you have to get a plastic card and add money to it. I prefer the ones with the cards, you usually get a bonus (if you put $20 on it they actually give you $24.) If you frequent the same laundry mat its nice to have a balance roll over. Also having to find quarters to do laundry makes laundry even worse.
Its been a long time since I've used a laundromat washer/dryer, I assume its all pretty similar. My clothes wash in about 25-30min, and dry depending on what setting around 40min.