I have a few items labeled "A maniac would buy for a high price, why won't he buy them?
Certain maniacs buy certain item he buys relic items and another example would be the berry maniac near nimbasa city
Beacuse he wants to buy the items you find in the Abyssal Ruins. The vases, the statues and the Relic Crown which costs 300.000 $
Have you get all the items from Abbysial ruins?
Those are the ones he buys.