Wizard's spellbooks have always been a pet peeve of mine.
For Example:
16 Intelligence, 5th level generalist wizard, found 2-1st level spells, 3-2nd level spells, 1-3rd level spell to add to spellbook. Always added highest level spells he could cast as free spells each level.
Spellbook Worth: 4,100 gp plus cost of found spells.
Cost of Found Spells:
1. 6 full-round actions to decipher the spells; Spellcraft DC 20 + spell level (unless he used Read Magic)
2. 48 hours to learn the spells (at 8 hours per spell); Spellcraft DC 15 + spell level
3. 1,100 gp to scribe these spells
4. 144 hours to scribe the spells into his spellbook (at 24 hours per spell).
Total Price for these six spells: 13 days, 36 seconds, 1,100 gp, and 11 pages. If the DM only allows 8 hours of work per day that increases the time required to 39 days.
This will take up 11 more pages of his spellbook for a total of 52 pages (19 cantrips, 10 1st level, 7 2nd level, and 3 3rd level).
Total Worth of Spellbook after scribing: 5,200 gp (5th level character wealth guidelines suggest 9,000 gp total).
Note: spellbooks are the only thing in the game that cost more to make than they can be sold for (the wizard’s 5,200 gp spellbook is only worth 2,600 gp on the open market).
And this is without any house rules to make it harder...
Ciao
Dave