The rather exotic sounding CSGOFliper makes upgrading your skins quick in easy. But rather than paying to upgrade or exchanging your old skins the website requires that you gamble them. By betting your old skins, you stand a chance to win better and newer skins of higher value. The system requires that you sign in with your STEAM account and choose the skins you want to gamble.
Beyond the basic layout, CSGOFliper does not offer any other method of upgrading skins. That said the system has a good win ratio so you can expect to win just as equally as you can lose which means that the system is pretty fair.