My objection to wizards learning new spells was the ridiculously (IMHO) inflated cost of scribing spellbooks - not the costs of R&D. A wizard who loses their spellbook is in enough trouble without it ALSO requiring 10,000 GP to replace (material costs alone)...
So. In my campaign, I drafted a number of house rules to address that and the processes associated with learning new Spells. They're not really 'done' - Mostly because the wizards in my campaign keep dying before they get around to using them extensively. I've got a new one starting though - so hopefully she'll express interest in developing new spells...
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Method Two: Research
a) Acquire a copy of the spell. Typically by finding or purchasing a scroll or book.
b) Decipher the spell. This can be accomplished automatically with Read Magic, or with a successful Spellcraft check (DC 20 + Spell level) - This takes One Hour/Spell Level. If failed, this can be re-attempted the next day. If the original scriber is assisting, this check is automatic.
c) Conduct experiments. This requires access to a lab or at least a basic 'kit' of equipment and any required material components. This process takes One Day/Spell level.
d) Attempt to learn the spell. This requires a successful Spellcraft check (DC 10 + 2/Spell level). If the wizard fails, she cannot attempt again until she has raised her Spellcraft at least One rank. If a wizard fails to learn a spell three times, she will never be able to learn it.
e) Scribe the spell into her spellbook. This takes One Hour/Spell Level and consumes Two Pages/Spell Level.
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Method Three: Development
Developing a new spell requires:
- 250 gp per day for library access, materials, and services*
- Research Time: Nominally Three Days/Spell Level
After the Research is concluded, the researcher must make a successful Spellcraft check (DC 15 + 2/Spell Level).
If succesful. the wizard may scribe the spell into his spellbook. This takes One Hour/Spell Level and consumes Two Pages/Spell Level as usual.
If the check fails, the wizard must repeat the process from the beginning.
Note: This Spellcraft check CANNOT be boosted by magic etc. unless the magic is in place during the ENTIRE research process
Accelerated Research: It is possible to rush this process, but each day of research skipped increases the DC by 5. Development requires a MINIMUM of One Day/Spell Level of study.
* This is the rate for Freelance (non-associated) Mages to use the facilities of the Guild/Arcane College in my main city. Members of the College pay less (in exchange for yearly dues and other obligations).
Masters of the College also get access to more advanced facilities, subsidized research lackeys etc. - which can substantially reduce costs or reduce Development time.
In any event, the Arcane College is often willing to PAY for the right to copy Developed Spells - which can further defray costs if one is willing to part with exclusivity...