Step 1: Get a Viettel pre-paid mobile card
50.000 VND ($2.5) -> get VIP Code (7 days used) || 100.000 VND ($5) -> 15 days
200.000 VND ($10) -> 30 days || 500.000 VND ($25) -> Lifetime VIP Code.
NOTE:
+ Where to buy? Ask for Viettel pre-paid mobile card at Vietnam town! More help?)

Step 2: Enter Card Info to get VIP Code
+ You should enter your valid e-mail for recover code if forgot.