Tempest Shop out in Ariant

And now you know why Nexon is being so generous with regular pchaos on Hot Days now.
Nobody will use them anyway, not when you can get twice the powa with these... and just a wee bit more NX.

Wonder whether there's any limit to how many you can buy per char.

Speaking of which, I noticed the clean-slates in this shop are the pure Untradeable kind, not the account-tradeable ones. Annoying.

Depends on how many you can reasonably hunt, but this is likely since I heard that the Positive Chaos from Hot Time expires in a week. Looking up Orange Mushroom's blog doesn't say much about how else you can get coins aside from another one where he mentioned ice boxes from monsters around your level. Oh, but check this out:

One other event has begun, called the Challenge! Tempest event. First of all, you can kill 200 monsters around your level to get 1 Tempest Coin (up to 10 times a day).

You can also hunt monsters in the new continent of Pantheon to get Tempest Celebration Boxes. Opening these will give you a variety of prizes including Tempest Coins, Buffs, Mount coupons, transformation potions, and surfboards~

Finally, you can get the Tempest Coin Bag, which when opened can give you 3 Tempest Coins, Tempest Coins plus an Intermediate Additional Stamp (10% chance of adding an Additional Potential line, 100% chance of breaking if failed), or Tempest Coins plus a 60% Chaos Scroll.

How do you get the bag? Well you have to participate in one of four challenges. Clear 3 Monster Park runs, 3 party quests, all four portraits in Spiegelmann’s Strange Gallery, or get to Wave 15 in Nett’s Pyramid.