here's the way it works in my current campaign
Our current DM has adopted a different method for this stuff. Maybe his ideas will strike a chord with you. Below is the full text of his house rule, copied and pasted from our campaign message board:
Scribing Spells:
Since scribing spells sucks in official DnD forms and makes it hard for a Wizard to be part of an adventuring group without excessive downtime, I will be adopting a variable time method.
Scribing Scrolls:
The cost to scribe a scroll is as follows:
1. 12.5 X Spell Level X Caster Level in GP
2. plus XP= [(Spell Level)squared]x2
3. plus time= 1 hour per 41 2/3rds gp in the value of the completed scroll.
These three items balanced allow Wizards to scribe magical writings. However, sometimes circumstances mean that one of these three items are lacking. For instance a wizard levels up and now has exactly the XP needed for the new level. According to standard rules this wizard would no longer be able to scribe scrolls because you may not drop levels due to XP costs.
Instead I am introducing a variable method to this.
1. Any of the 3 items may be halved or doubled by respectively doubling or halving another item. example: double the time and halve the XP cost. You may do this multiple times. example: quadruple the gp cost and quarter the XP cost.
2. Once you have determined #1 you may buy off any remaining Experience Points in the XP cost at a rate of 5 gp for each XP.
These two variation methods allow the wizard to choose a method of scribing to suit available resources.
Adding Spells to a Spell book.
The standard method still applies as it allows wizards to learn new spells without XP costs, albeit at a prohibitively slow rate.
Additionally, if a wizard wishes they may instead substitute the method outlined above to add spells to their spellbook, as if a scroll were being written into the spellbook.
