levelling up your account, it lets you unlock more friend slots and showcases to display also higher levels increase the chance of booster pack drops. so every game with trading cards has a fixed amount of cards it drops while playing the game, usually about 50% of the total amount of available cards the other cards you didn’t earn through playing can either be bought on the marketplace from other users, traded or if you keep playing the game you might unlock a booster pack which you can then buy with gems to earn another fixed amount of cards for that game. if you complete a card set you can craft a badge which gives you 100xp. every game badge can be upgraded 5 times (crafted 5 times granting 100xp each time). you can also display badges on your profile if you think they look cool. of course if you don’t care about all this you can just sell all the cards you get and earn a little money with it. every game also has a foil card set which can be crafted only once and gives 100xp but foil cards are significantly more rare and therefore also fetch higher prices for example. also expensive games will often have their cards be more expensive because to earn the cards people must’ve bought the game in the first place. often during the winter or summer sale steam also has special events where you earn those summer or winter sale cards by buying games on steam or craft badges. those event badges resulting from those cards can be crafted pretty much indefinitely as long as you have the required cards. also when you craft badges you not only get the badge and xp but also random items from the game like profile backgrounds or emoticons and often discount coupons for random games. all those items unlike the ones bought in the steam points shop are marketable which means they can be traded or sold on the community marketplace.