My players have completed Thirteen Cages and saved Cauldron from total disaster. Of course, a lot of damage was done to the city's south east quarter.
One of the characters was elected mayor of Cauldron. They are now busy dividing the treasure found in the Sanctum. Of course this is worth quite a lot of money. They want to use part of it to help rebuild the city. Does anyone have an idea how much this should cost? Or where to begin looking for prices?
You could look to the Stronghold Builder's Guide for suggestions about building costs. As for fixing the volcano itself...it's not so much money as intense magical application that would be required. I'm not sure where you're going to get building materials to reconstruct a volcano.
Rebuilding the volcano will be slow, but can probably be done by using a lot of castings of Fabricate (1 cubic ft/level when using minerals). If you have access to Polymorph Any Object, it would go a lot faster (100 cubic ft/level).
I don't think they're planning to rebuild the volcano itself. I believe they're thinking about building houses for everyone who's become homeless, rebuilding roads, maybe looking into the defenses of the city. Stuff like that.
I will take a look at the Stronghold Builder's Guidebook. Bought it long ago but never used it.
Ah. Then they should invest in a Lyre of Building:
Lyre of Building
If the proper chords are struck, a single use of this lyre negates any attacks made against all inanimate construction (walls, roof, floor, and so on) within 300 feet. This includes the effects of a horn of blasting, a disintegrate spell, or an attack from a ram or similar siege weapon. The lyre can be used in this way once per day, with the protection lasting for 30 minutes.
The lyre is also useful with respect to building. Once a week its strings can be strummed so as to produce chords that magically construct buildings, mines, tunnels, ditches, or whatever. The effect produced in but 30 minutes of playing is equal to the work of 100 humans laboring for three days. Each hour after the first, a character playing the lyre must make a DC 18 Perform (string instruments) check. If it fails, she must stop and cannot play the lyre again for this purpose until a week has passed.
Faint transmutation; CL 6th; Craft Wondrous Item, fabricate; Price 13,000 gp;Weight 5 lb.