When you play sng's you want roughly 50BI. So if you start at say, 50c 45 mans, you want at least $50.00. Cash you want 20BI, mtt's you want at least $100.00.
Keep reading and applying strat and you'll start winning in no time. Don't worry if you're losing the for a while, you'll start winning as you get better.
Real poker is nothing like the home games you have with your friends, especially if it isn't for real money
Gl at the tables.
PS: when you go to uni, don't blow your student loan for the three months playing $2/$4 online/at your local casino.