insufficient balance your sim is eligible but if not you would be told your sim isn't eligible.
2. Subscription code *567*58# cost #100, *567*59# cost #150 both are unlimited, when you subscribe for that of N100 you would be told you subscribed to the 100mb unlimited plan, that of #500 you would be told 500mb, don't worry it is not limited, subscribe and download as much as you want tested and confirmed by me.
3. This is far better than Mtn BBLITE because this one requires no application, you just subscribe, insert your sim on any device and use, you can share your data connection via Wifi.
Is it helpful?