League Of Legends
Originally Posted by Terms of Service: Section IV, BThe sale or transfer of Virtual Items or Riot Points between users may only be conducted via services approved of and provided by Riot Games, if any, and Riot Games may terminate any Account that acts in contravention of this prohibition.
It's legal on Riot's end and I'm pretty certain it would be legal on Toribash's end as stated in the thread linked above. I would PM an msquad member for a quick(er) official response.