If you're goind down this path then the investment in Bartering + Charisma (and grabbing politician) is certainly worth while.
For the few points you "give up" you're gaining many more.
I also highly advise gifting money to the NPC. With a reputation of 100, and a few pieces of bartering gear, you'll pay face value AND be able to sell items to get your original investment back.
I did this (though unlocked @ lvl 6 because I chose a different path) and have had no money issues. At all. Every level I have purchsed these books and have an inventory full of gear waiting to level up so my vendors will restock their gold and I can unload said gear.
