I haven’t really messed about with Steam Achievements or Trading Cards too much.
But I noticed that I have a lot of duplicate trading cards in my inventory. There seem to be 2 options: Turn the cards into gems that can be used to create booster packs, or sell the extra cards for a few pennies and save up enough for a cheap game or two.
What are the booster packs and what do they do? I clicked on the “learn more” link, and it unhelpfully informed me that I can “Make booster packs from extra Steam Community Items in your inventory.”, and “Recycling Community Items gives you Gems that can be used to make new booster packs.”
But it doesn’t have any information on what the booster packs are or why I would want one.
Booster packs have a few Steam trading cards for one particular game. In other words, they are just pointless fluff for the people who like fiddling with the Steam cards.
Once you have a full set of cards for a particular game you can craft a badge. A badge is really nothing special, it’s just something on your Steam profile that indicates you liked that game enough to collect all the cards for it. You do get XP for crafting badges, which increases your Steam level, which allows you to add more friends.
FWIW, I would sell the duplicate cards instead of making gems. I have done both and the investment in gems is much more of a hurdle than making .10 per card. Just make sure you look at the graph to see what they are selling for. Your profit has to be slightly below that (so they pay .10 but you only get $.08) but the cards will sell almost immediately.
Edit: you need booster packs because you cannot earn a full set of cards from playing a game. You have to either buy the missing ones or get them in booster packs. However, booster packs will usually contain duplicates of ones you already have so buying them on the market tends to fill in the holes much more efficiently than hoping for booster packs.
Generally speaking, a Booster is worth a penny or two more than the average value of three cards from that game. That’s because you theoretically might get a foil out of it. In reality, you’re almost always better off just selling the booster and getting the couple extra pennies.