Go to your nearest convenient store/gas station, walk in, get papers, go to the counter, and plop down the papers and the money. just act like you do it everyday and most clerks won't question you. if they ask for ID just be like, "sorry, I left mine at home" and leave. If your really desperate, try asking people coming into the store if they'll buy you papers (just be like "I left my ID at home man, I'll pay you a dollar + cost of papers if you buy some for me", or check the story every couple of hours until the clerks change shifts (to try the casual approach again.)

Then there's always EDIT and other various online shops, if you can get the mail without your parents knowing, you can usually buy them online, order in bulk to keep the shipping cost/items ordered ratio good. The only problem with those is the wait, which is why I would recommend ordering in bulk.