Water of Life is an important commodity in Angel Land, as it can recover Pit's life. It's found in different quantities, sometimes during Pit's journeys (never in Fortresses), but also in stores. Pit will need a Water Barrel to carry more than one bottle of the Water of Life.
Picking up a Chalice will recover 7 HP. Note that Chalices will disappear if Pit enters a Chamber without picking it up.
Merchants sell Chalices for 210 Hearts. A successful bargain brings this down to 100 and failure will raise it to 400.
These will only kick in once Pit's HP reaches 0, where it will immediately recover 7 HP and save him from death, regardless of any "over-damage"; the Bottle is then consumed. Pit can only carry one Bottle unless he possesses a Water Barrel, which increases his capacity to eight.
Merchants sell bottles for 350 Hearts. A success bargaining drops this to 270, and failure raises this to a prohibitive 760.
Goblets are dropped by enemies and sometimes found in the area itself, but they are not sold by merchants. They recover only a small amount of Hit Points.
This item recovers one block of Pit's life and actually returns if Pit picks one up and then enters and exits a chamber.
Pit can buy this for 100 Hearts in a normal stage, but they cost 150 in a Fortress.
This item acts like a Chalice when Pit's HP reaches 0, immediately being consumed to recover a block's worth of life and saving him from being defeated. Pit can carry only one unless he also carries a Water Barrel, in which case he can carry eight.
On the surface, Pit can buy Bottles for 250 Hearts. In a Fortress, they cost 300. Black Marketeers sell this for 300 as well, but can be bargained down to 150.
The Drink of the Gods fulfills a similar function to Water of Life.