In documents revealed during the Oracle v. Google trial today, Google mentioned to T-Mobile back in 2006 that it wanted to turn the carrier plan pricing structure on its head by underwriting part of the cost of an unlimited data package. By Google's math, customers would pay $9.99 a month for unlimited data — to subsidize the reduce cost, the company would forgo the commission it earned from T-Mobile for referring Android buyers to its online store. Google figured that its own services — Gmail, search, and so on — would consume about 15MB a month, a figure likely estimated to be far lower in 2006 than it is today.
The first retail Android phone, the T-Mobile G1, would ultimately be made available with $25 and $35 data plans, so Google's vision was never realized.