I live in Peru.

I pay 10 PEN ($2.70) and get:

• 10 GB data (plus calls and SMS) only valid for 7 days. This is “free” and does not discount my credit.
• Once the 10 GB are up I pay 5 PEN for 24 h of UNLIMITED GB (Yes, I can tether too!)
• Once the 24h are up I do this again with the remaining 5 PEN
• Therefore on weekends I get unlimited internet.
• My speed is around 18 Mbps (2.25 MBps)
• I do not pay for home internet and simply tether to my laptop.

So it all works out at paying around $10 a month for unlimited internet (as long as I download the big things on weekends!)