Regarding money, if you give the Teller gold for free you will increase her attitude permanently, up to a max of 100. That means it will no longer be necessary to invest in Charisma to reduce prices. If you plan on buying many books, it's more than worth it in the long run, since a 15k-20k investment can save you over 100k in gold. It also means that she will give you the best possible prices when you sell stuff. So unload your pricey items on her until she's out of gold, because she'll give you the best deals.
But like Thorsten said, this seems like major overkill...even on Hard mode, the game is easy enough that you don't need to make your characters god-like to get through it. Seems like this would make the game really boring!
