The Armor Shop sells items which will make your hero survive longer in the field. These items are generally much more worth their cost than the items in the Weapons Shop.
Crown of Kings +7 (1150 gold) 
Edit
This item adds +7 to strength, intelligence, and agility.
Belt of Giant Strength +10 (350 gold) Edit
This item adds +10 to Strength, which increases health, health regeneration, and (for Strength heroes) damage.
Boots of Quelthalas +6 (350 gold) Edit
This item adds +6 to Agility, which increases attack rate and armor by 2.
Robe of the Magi +7 (350 gold) Edit
The Robe adds +7 to Intelligence, which increases mana, mana regeneration by 0.35 Mana/sec, and (for Intelligence heroes) damage.
Sobi Mask (250 gold) Edit
The Sobi Mask increases your mana regeneration by 100%.
Circlet of Nobility (350 gold) Edit
Grants 2 to all stats.
Precept of Mana (450 gold) Edit
The Precept adds 200 mana to your hero.
Ring of Regeneration (350 gold) Edit
The Ring increase your health regeneration by 3 hit points per second.
Ring of Protection (200 gold) Edit
The Ring of Protection grants your hero +6 armor.
Medallion of Glim (350 gold)Edit
This quirky item gives you +4 armor and 100 additional mana.
Bezerker's Mask (300 gold) Edit
Reduces damage dealt to the hero by 7. and makes the other hero suck your dick
