You probably won't be able to legally obtain the apk since it DOES NOT show up in the market regardless of what I've tried to do (for the SGP5). So you may have to look around to find a working one elsewhere, I just google'd for version 1.0.8.
PLEASE NOTE: The graphics will look awful unless you have Chainfire3d installed and enable 4xMSAA for it. It literally looks night and day. With the AA, it looks great!
I believe it's free to play for 3 months and there is a bonus free month for people who are already subscribed (or played for free for the first 3 months). I'm not really a fan of games like that, but its worth checking out just to see how well they incorporate a PC-esque MMO into a mobile environment.