Easy - that's the price you pay for having unused data that does not expire at the end of every month/billing cycle. Same goes for the price per minute. América Móvil is very, very smart about having multiple brands to satisfy a magnitude of usage patterns while maximizing profit. They'll get $ from light data users on TracFone, and they have their other brands for those who need unlimited voice/text/data.
Page Plus charges $0.99 per megabyte and Airvoice charges $0.066. Even at AV's rates, that's nearly $70 per GB. Again, just the price you pay for pay as you go. I find TracFone's rates very reasonable and with the wide availability of WiFi these days, I can see where one could add a 2GB card and be set for the year.
Castrol EDGE 5W-30 is my drug of choice.
Primary: iPhone 6 64GB, Galaxy Note 3, Galaxy Avant: 5 lines, 3x $5 Android web, 1x $2.99 T-Zones, corp discount + $10/mo loyalty discount = $93/mo tax inclusive
Secondary: Galaxy S3 LTE & iPhone 4S: TracFone (Verizon)
Mobile Broadband: HP Stream 13 w/ T-Mobile 4G & iPad Mini Retina w/ T-Mobile 4G LTE ($10/mo for 5GB with hotspot)