During the Summer Sale on Steam you can get 14 animated stickers and a frame for your profile.
You can also get a 1 free trading card per day – you can sell that card to get some Steam wallet credit or use it to make a badge.
How to get the stickers and the frame:
Just go to the main link, log in, click on each genre, and make a choice. You will then get one sticker for the choice you make in each genre.
After you have gone through all 14 genres, you also get your frame. You can then also read your story (being made up of all the choices you made previously, kind of a very simplified choose your own adventure).
How to get the free trading card:
Go to your discovery queue and go through it once a day. Essentially, that means looking at 11 games per day.
You can come back each day until the sale ends on 9 July. You will be able to get one card per day (one run through the discovery queue).