Items

Circlet + Mantle = Null

Items

Recipes

Recipes are another unique part of DotA, which makes the game distinct from the crowd. Recipes, likes its namesake, means you can combine items + items = more uber items.
Shops
L1 Recipe Shop: Human Shopkeeper
L2 Recipe Shop: Orc Shopkeeper
L3 Recipe Shop: Night Elf Shopkeeper
L4 Recipe Shop: Undead Shopkeeper
New Recipe Shop: Blood Elf Shopkeeper (top left of other Shops)
Secret Shop: Leragas the Vile in bottom-mid-left / top-mid-right
Note: Wood is not used in DotA. If a recipe says requires 1 wood, it just means you need to collect the items and it will transform automatically without actually buying a recipe