This device/deal is for Straight Talk customers. The only way to unlock this device is by using it for 12 months on an active/paid Straight Talk plan (see their plan prices/features here[straighttalk.com]). There is no other way to unlock this device (and RSIM no longer works)
It can also be used on Total Wireless, TracFone, Page Plus and NET10 only (since they are all owned by the same company - America Movil). YMMV however on if any of those other four services it's compatible with besides Straight Talk will unlock it for you after a year (have heard both success and failure stories about this).
It can be used as a WiFi device (like an iPod Touch/iPad), without ever needing to activate it, if desired.