It has an Item Level of 1 and requires a character level of 1.
"When the demons come, close your eyes and ring this... it takes you far, far away..." —Unknown
It can be purchased from Squirt the Peddler in Act II for 100,000 gold (25,000 on consoles). It is account bound upon acquisition. Wirt's Bell is always available from the vendor; unlike the other items used to craft the Staff of Herding.
Wirt was a young salesman in the original Diablo who was mutilated by the Fallen within the bowels of Tristram Cathedral. He has left his mark on all three Diablo games; in Diablo II, his corpse can be found within the ruins of Tristram, and his leg is used to open the Secret Cow Level.