Joining a guild allows you to not only sell extra rare items, materials, recipes, etc you find in the game but you also meet a much of awesome people whom you can go around and do Public or Group dungeons with and other things, especially once you hit Craglorn and need to group up to do things.

I am not sure how you join one on the Consoles, but there is a section in the forums here if you look at the categories for Guilds where they post if they are recruiting. You can then give them your userid or whatever and they will add you when they are online next.

Advantages are many, being able to call upon help for PvE or PvP operations.

Help in levelling crafting professions, or having items crafted for you at more reasonable rates than you would experience typically in zone or guild kiosks.

Most guilds in my experience on PC/EU do WW/Vamp bites for either free or for a reasonable price lower than the average 3/5k asked for in zone (never pay more than 5k ever:P)

A lot of guilds focus on stuff on PvE/PvP and trading, so there is a community there to be part of, or do as myself and many others have, create a guild and take it to greatness:}

Look in zone for people asking for peeps to join guilds, some are word of mouth also.

And apologies if you are console, but I imagine most of the game is similar to PC.

Then there is a guild bank unlocked at 10 members, although it largely depends on guild protocols if you can access them, as there has been many cases of stuff being looted by dishonourable people in guilds.

There can be a guild store unlocked at 50 members, where you can buy and sell.

Guild tabards

And many more reasons, join them, you can join up to 5 guilds, including one you can create.

Most do a mix of trade and PvE/PvP guilds to gain access to all areas of the game.

Hope that helps.

You are welcome, enjoy:}