You need only a few clothes or special clothes, if you play on a football team they give you the shirt and trousers for playing matches normally on Saturdays, against other teams of your League. You should buy a pair of football boots to play matches, and a pair os special shoes, but the color depend of your team equipment but they are usually black.
Places to practice it:
In my city football is the most famous sport, and most of all the kids play it, so there are a los of stadiums were you can practice it. But for playing on this stadiums you should ask for permission to his propietary, and usually pay something that depends on the hours you ocupate the stadium.