The subscription-based model for MMOs is well and truly dead. With the exception of stalwarts such as Blizzard's World of Warcraft, it seems every massively-multiplayer online game eventually switches to free-to-play. In the case of NCSoft's WildStar, it took less than a year for the developer to drop the need for regular payments, in exchange for optional costs.
The details of the transition from subscriptions to free-to-play are laid out in a rather lengthy post on the official WildStar website. The long and short of it is that all aspects of the game will remain accessible, with "completely optional in-game purchases" for cosmetic and "convenience options" providing revenue.
There's also a two-tiered system if you do feel like committing to regular payments. While Free players don't gain any specific benefits, a "Signature" customer will be provided a bevvy of bonuses, from reputation and experience buffs to the ability to create guilds and "circles".
If you're a current player and have paid up in advance, the announcement states you'll be converted automatically to a Signature account for as long as your subscription is in the black.
You'll also be rewarded for your previous playtime before the F2P conversion in the form of "Loyalty Points". These will eventually be used to acquire "special items and perks", with a few detailed later in the post.