By the time you are reading this Aion will have launched in North America. For those of you who like to have a leg up on the competition, it'll be a good idea to know the places that will be selling Aion Kina as soon as possible. You don't want to end up going to a scam site or something equally crappy just because you were in a rush, so we'll talk about some of the top quality sites that will be good places to buy Aion Kina in the days to come.
The very first quality site that I'm aware of that will be offering Aion Kinah is SwagVault. This company is a major player in the currency industry, mainly because of their well-documented reputation for good deals, good service, and fair prices. In addition, SwagVault is known for always taking extra steps to make sure their customers don't get busted. If you are someone still asking "Where can I buy Aion Kina?", then SwagVault is a great site to check out.
The other site that comes to mind is of course my personal favorite for gold buying, IGE. IGE doesn't supply for every game, but they have been advertising the launch of Aion Kina sales for a while now; that makes sense, seeing as how Aion already is the second biggest MMO in the world and it isn't even out in the western world yet! For those unfamiliar with IGE, the site is known for being a safe place to buy from, having good customer service, high availablity, and some of the lowest prices on the internet. They don't engage in risky behaviors that put their customer's in a tight spot, either. A good choice for buying any game money they provide for.
There will no doubt be other sites selling Kina from day one, but many will be low-grade sites with unsavory reputations, or sites that participate in immoral practices such as botting and spamming in-game. There are other good sites than the two I mentioned, of course, but these are sites I have myself used frequently with great results every time, so I feel most comfortable recommending them as the first place to look for anyone starting the new MMO and looking for an edge. I hope this has helped you out in your search for Kina!
If you are curious how SwagVault and IGE compare to one another and some other popular gold sites, by the way, feel free to check out my comparison review post, MMO Gold Sellers - A Comparison Review.