I am in a situation here where I am an LE Priestess of an LN deity, and I have met with a Paladin of my said deity.

I was wondering if there is an exception to the paladin no eBol rule, in the terms of working together, since the two would work to the same end most of the time.

What about buying wands from said cleric for the paladin, would he be breaking his oaths in this situation if he bought wands from the evil cleric of HIS deity?

No, the Paladin would react as they would to any evil person. By their point-of-view, you are corrupting your shared deity's word with your ill morals.

So that's a 'No' to the first question and a 'Yes' to the second.