Since it is only a small chance that it will be sold this is a good point (but boring) to see if luck affects what a merchant happens to sell.
I think I'm going to do hundred or more (needed to get some decent statistics on it) jumps to a battlefield and look at the different merchants.
That char has 127 luck atm.
Then I'll start over with the game to get to the same battlefield but now with a 'normal' luck char and do the same.
To Larian:
Please tell me (if needed in a private message) that the merchants in any battlefield have this chance instead of just Act IV because the char I'm going to try this with is not yet in act IV.
