Maybe you can get these people to rent you a SIM & it might work in other devices with same tinkering:
iPhoneTrip: travel with iPhone, unlimited internet SIM card
It should work out to be cheaper provided you utilise it a whole lot & replace other things with it like regular phones with VoIP.
Active SIMs:
2007-05-14: T-Mobile post-paid (USA: 267)
2007-12: T-Mobile pre-paid (USA: 857)
2009-01-21: Mobal World (UK)
2010-06-08: TracFone (USA: 215)
2011-03-12: Tru (USA: 305)
2011-08-01: AT&T pre-paid (USA: 212)
2011-08-22: Spot Mobile (USA: 603)