found this but i cant see the pricing..i beleive the 50 for 500mb is the standard usa data usage which can also be upped to 60/2.5gb per month
*** Included data at up to 2G speeds. High-speed data passes available for purchase.
With your plan you get unlimited international data at 2g speeds. To get faster international internet its $50 for 500mb.
This is from a cnet.com article:
"For $15, a customer gets a single day's worth of high-speed data up to 100 megabytes, while $20 gets one week at 200 megabytes and $50 gets two weeks and 500 megabytes"