I don't know if this is legal or not. Might be, might not because it's a little bit of a gray area. I'm not trading anything in REAL LIFE but I'm trading it for something other than RuneScape stuff. If this is against the Terms of Service, please notify me. I do not want to break any rules :P
However, if this is NOT against the ToS, then I have about a 250m bank. I would like to sell gold for 1,000 CE per 3m.