Unless you're World of Warcraft—which has been seeing declines of its own, mind you—the MMO market is a tough place to be. Following the example of Asian MMOs, most in the genre have ditched the subscription model in favor of free-to-play.
Even BioWare's Star Wars: The Old Republic, which started off with a strong launch—enough for it to be dubbed a possible "WoW killer"—has been facing heavy drop-offs in numbers. In the most recent months, SW:TOR's reported a 400,000 drop in subscriber base. It's really not surprising to see, given the fact that the MMO is story-driven and that the developer is pumping out new materials slower than the rate at which players consume them.
SW:TOR first dipped its toes into free-to-play earlier in July, when BioWare and EA announced that the game would be free-to-play for friends of subscribers up to level 15. Apparently, the scheme to get new players worked, as EA today announced that SW:TOR would be going completely free-to-play up to level 50.
The game's subscription model hasn't been done away with. Instead, BioWare and EA are offering perks to subscription members, who will gain monthly grants of the game's new virtual currency, Cartel Coins, to spend on in-game items.
Free-to-play members will have certain content locked out that can be granted when they decide to purchase them with Cartel Coins. However, in order to grab all content, a paid subscription must be had.
Starting in August, SW:TOR will go on sale for $14.99, with a month's worth of complimentary subscription.
The free-to-play with subscription model is a good one to have for a story-driven MMO such as BioWare. It'll hopefully motivate free-to-play players who hit the level cap or are drawn in by the story to shell out the subscription necessary to keep on playing.