NC's September 18 update disables direct trades between players; the Market remains available. That is a different question from how much Kinah a character earns. It changes the route an item can take from one player to another.
Old assumptions need checking
If your group's launch plan involved handing a spare weapon straight to a friend, stop and check the new rules before building that plan around a trade window. A Market listing and a direct exchange are not interchangeable. Likewise, a search result advertising an Aion 2 Kinah boost does not establish that its proposed delivery method works or is permitted.
Price predictions can wait
Our view: observe actual listings before treating this as proof that prices must rise or fall. Supply, demand and transaction restrictions all matter; this announcement alone supplies no reliable price forecast. Keep your first shopping list short and separate what you need from what merely looks cheap. Recheck official notices when you start playing, especially if you saved an older description of membership benefits.