Thankfully you'll probably start at at least level 7 or 8, because you get some free experience for how long you've had your Steam account and how many games you own. So it costs 100xp to go from level nine to level 10, but 200xp to get from level 10 to level 11. Every ten levels the amount of experience needed to go up one level goes up by 100xp. Unfortunately leveling up suffers from diminishing returns.
You can up your chances of receiving a Booster Pack by upping your Steam level, every ten levels your chances of finding a Booster go up by 20%. Booster Packs are awarded at random, you don't even need to play the games to get one, you just have to log into Steam once a week. Each pack contains three random cards, including a small chance of finding a 'foil' card, which is worth ten times as much. Once you've earned all your regular drops, you become eligible for a Booster Pack.
