You cant...however, you can sell your cards at the 50 clintz minimum through a private sale. If you have any credits, you out of luck since those are non-transferable. As far as giving away your clintz, buy their cards at inflated values (assuming that they can sell on the market). But you can not give you stuff away for free.
The Urban Rivals team is made by lovers of all kind of Collectibles Cards Games and Trading Cards Games like: Magic the Gathering, Dominion, Vampire, Yu-Gi-Oh!, Pokemon, Wakfu TCG, Assassin Creed Recollection, Shadow Era, Kard Kombat and Might & Magic Duel of Champions.