You can buy "Gems" for real money. Gems are the item shop currency and can be sold ingame to other players for gold. You cannot trade "Karma", "Fame" and "Glory" which are earned by players and their guild for participating in pve and pvp activities.
Item shop unlocks are for "account services and on time-saving convenience". To generate a demand for "time-saving convenience"-items, Anet must have left inconvenient game mechanics in the game ..so much for the promise of "no grind, just fun".
In World vs. World you can buy siege weapons and other bonuses for gold -> pay2win..