Well, tmobile's 200MB free data plan works too (for now).
Couldn't activate a unused Sim directly on the tablet (redirected to T-Mobile site when Sim is inserted, but said "device not supported"). A pre-activated Sim works
Since I have postpaid tmobile as well, I have the 1GB free plan, and it throttles to 2g when I go over(free 200mb users get hard cut off instead of throttle)
Verizon's prepaid data plans obviously works too, but its very hard to get a Verizon Sim to use ( they get deactivated after 6? Months of no active plans, need to get one from fleabay. Most Verizon stores refuse to give out Sim cards , or would activate you for postpaid even if you asked for prepaid ). $30 for 2GB
Oppo Find 5 - experimental kernel