On a fresh account, you’ll have access to the whole base game (but not the DLC). You also pick up 500 crowns to spend in the cash shop. “Any characters created, Crown Packs purchased, or Crown Store items bought, as well as any progress made during the Free Play Week will carry over when you purchase the game,” ZeniMax says, in the hopes that you will indeed purchase said game. Plus:
“During the Free Play Week, you’ll enjoy a discounted price on either The Elder Scrolls Online: Tamriel Unlimited (the base game) or The Elder Scrolls Online: Gold Edition, which includes the base game as well as the four major DLC packs: Imperial City, Orsinium, Thieves Guild, and The Dark Brotherhood.”
Newbies can hop in and start downloading the game as of 10 a.m. EDT on Tuesday, April 11th.