Really simple:
-Enter Kenebrook's Basement Quest (Just east of The Leaky Dingy)
-Grab the page from the cabinet behind the crate
-Exit & repeat as desired (you won't loose any xp if you're concered about that)
-Trade to Giles Goodman just outside of The Leaky Dingy in stacks of 3
-Reward: Scroll of Shield of Faith or Scroll of Feather Fall
This gets old quick & should only be used if you need to learn these spells or just want a stack of scrolls. Shield of Faith is good to have around if you can't cast it. You could sell them for 7 gp each but there are much quicker ways of making money in this game.
Note: This only takes about 30 seconds per run.