It constantly needs raw materials to build or something. Unfortunately, the collected raw materials are often insufficient. If you have the story through, you can buy (with enough Studs) at Erebor. It simple, but always arises a question: "Where can I get the enough material / resources?"
You can buy other commodities and also some raw materials from vendors. Their locations (completeness is not guaranteed), and the best places to find a particular commodity should be enumerated below.
Some mining stones are always there and always offer the same raw material. Most of them are available occasionally and they have always another commodity. Especially many of these are:
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- Cave near north of Bree (where the design Mithril Mushroom Crown)
- Barrow-downs, particularly in the cave
- From the Trollshaws the edge of the west, then follow the arrows
- Cave on the summit of Caradhras - (required fire - dragon)
- Cave near Moria (with bars)
Now to the individual commodities:
Copper:
- Mining stones at Trollshaws
- Distributor: above the Troll camp
Iron:
- Mining stones around the Weathertop
- Carts in the Shire
- Distributor: Southern Barrow Downs near the river
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Silver:
- Dealer on the way from to Beorns the same gate of Mirkwood
Gold:
- Kegs on Trollshaws
- Level 1, Section 2
Rubies:
- Only in random mining hills
Sapphire:
- Distributor: outside Bree Coming from Bywater. Coming; at a lake to the south through the cave you come Weathertop.
Emeralds:
- Traders: on a lake to the south to get through the cave Weathertop
Diamonds:
- Dealer in Thranduil's kingdom, from the river with the barrel up the stairs
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Wood:
- Bushes and trees - everywhere
Leather:
- Kill enemies (eg in the Battle of Moria in Level 3, Section 2)
- Wooden crates on Elven Port
Rope:
- Bushes and trees - everywhere
Bricks:
- The breakdown of mining rocks as a byproduct
- All kinds of rock - especially in the high mountains; Statuary
Carrot:
- In the Shire, particularly around the cornfield in the soil and in bowls
- Around Radagast's House
Bread:
- In the Shire in numerous open boxes
- In boxes in Thal
Meat:
- Kill enemies (eg in the Battle of Moria in Level 3, Section 2)
- Traders: in the square of Bywater
Fish:
- Everywhere in seaside town
- The river in Bywater
- Distributor: Elven Port far west; the High Pass above the waterfall