In Home | CSGOBankBot you get 7 points when you login with steam, then you go to the main page and search for an skin with price 7 or less, you add it to the cart and checkout. (Free $0,07 skin)
In https://csgospeed.com/ you login with steam and go to the Recruits page, in Enter Code you put F6978672E5 and you get some free money, then you need to bet this money at the Heads Up page, if you win sometimes you can get a skin.
In https://beta.hypeskins.com/r/76561198058063525 you get some ''diamonds'' and you can enter Skins raffles with them. You can enter free raffles too. (I just won $2)
At csgodicegame.com/?r=568f1ab08d4dacc0202b33f4 Login with steam, you get 5 coins, if you put CSGODiceGame.com in your steam name you get 3 coins PER DAY, so then you can eschange your coins for skins at the Withdraw page. You can bet this coins with a winchance that you decide (High recommended)
At http://csgohouse.com/?rid=76561198058063525 you login with steam and get $15 (from the page) with these you can bet or exchange for skins ant the Market page.
At $1.55 :: CSGO Reaper.com you login with steam and click Continue Anyway, you got 25 points that you can spend on the market icon nest to your steam photo. (free $0,25)