Because of NDA, a lot of people can not gave out examples: We know about guild stores and almost every MMO has player to player trading as well.
We can't say for sure without breaking NDA, nor can we say what the economy will be like until a few weeks into the game at launch.
However I would definitely think you can directly trade with another person, Ie. give them items, do a trade deal and what not.
And there are the guild stores in Cyrodiil where you can sell your wares.