Hervis said:
The wizard in my party want to make an item that would give a +2 bonus to all Knowledge skills. You would still need the skill to use it, but all knowledeges that you have would get the bonus.
How should I price this item.
Well, a stone of good luck, among other things, grants a +1 bonus to
all skill checks. The stone accomplishes three things (attacks, saves, skill checks), so the quick and dirty breakdown is that the skill bonus thing is roughly one-third the total price, which is about 3,300gp.
A +2 bonus to only Knowledge skills wouldn't be as costly though. Here's an example. Assuming that a character wouldn't have need for more than ten Knowledge skills anyway, I'll start with that. A +2 bonus to a skill is worth 80gp. A second +2 bonus to another skill, on the same item, is double that (if the item takes up a slot). So, we have 80 + (160 x 9) = 1,520gp. So, you get a +2 bonus to a total of only 10 skills. Comparing that to the Stone of Good Luck, which gives the bonus to
every single skill, I can safely say that my price isn't too low. In fact, I think it might be too high, but I wouldn't suggest lowering it below 1,000gp. After all, Knowledge is a useful skill, but its not
that useful.