As well as I know, maya items requires 2000 qi to be unlocked, but I saw a people that only have 500 qi can wear a maya relax. How can he bought it?

Info:
http://forum.toribash.com/tori_shop_item.php?id=1165
http://forum.toribash.com/tori_item.php?invid=2597967

Here is the user achievement:
http://forum.toribash.com/tori_achie...ame=LoneSkills

It is possible to purchase full item packs which have a 'no qi restriction.' It is also possible to win items which require 0 qi, from certain events, or to buy them from the marketeers via the market.

Note that once the packs are opened, or once a 'no qi restriction' item is added to your inventory, the item then depreciates and will have a qi restriction when traded.

Qi restrictions are only ignored when the items are sent by special users e.g. gm prizes, marketeers, TSAs. Just to be clear, there are no such things as "no-qi items".