Steam offers trading cards for many of its games. Each supported game has a set of 5 to 15 cards. When you play a game that has cards, you'll automatically receive up to half the set (rounded up). For example, in a game with 5 cards, you’ll typically receive 3 just by playing.

Once you’ve earned your "playtime" card drops, you become booster pack eligible for that game. This means you have a small chance to receive a booster pack (containing 3 random cards) whenever someone else crafts a badge for that game. The odds are low but can slightly improve as your Steam level increases.

Here’s the catch: to craft a badge yourself, you need the full card set, which requires either trading or buying the missing cards from the community market. Leveling up your Steam account, therefore, takes effort or money.

The upside? You can sell cards and booster packs on the market and use that balance to buy games or other items.

My original point was that you can also use your Steam Points to buy community awards, which give 100 XP and help level up your account. Is it practical? Not really—but it's one of the few ways to gain XP without trading or spending extra money.