Resources and Needs
Resource: The steading has easy access to the listed resource (e.g., a spice, a type of ore, fish, grapes). That resource is significantly cheaper.
Need: The steading has an acute or ongoing need for the listed resource. That resource sells for considerably more.
Dungeon World SRD
Curiously ill defined in source material, plus expansion of the context to include post-apocalyptica. Here we go:
(-1) Clean Water
(=0) Clean Water + Crops (Grain, Legumes, Fruits / Vegetables, Herbs / Tea, Spices, Veg Oil)
(=0) Clean Water + Textile Crops (Cloth, Linen)
(+1) Clean Water + Crops + Livestock (Meat, Fat Oil / Tallow, Candles, Mounts)
(+1) Clean Water + Crops + Textile Livestock (Hides, Leather, Wool, Silk)
(-1) Game (Fish, Meat, Furs / Pelts)
(=0) Honey
(-1) Timber
(=0) Timber + Minerals or Metals (Stone, Ore, Salt, Hydrocarbons, Precious metals, gems)
(+1) Timber + Minerals + Blackpowder (+1) Salvage (Stone, Metal, Industrial Components)
The given modifier is the equivalent Prosperity level granted by the Resource in question. How exactly that maps to a steading with a need for the resource is a slightly more advanced issue, I think.
Mutant World 