回复：你说的这两点应该更不是问题，不是dream :)

Pure data plan would be more expensive when not bundled with voice plan. Wireless carriers do not like data-only plan because it hits their fundamental voice revenue. Google voice is not VOIP but a voice router. You have to have a good-quality voip provider and stable data network. If there is outage or traffic jam of data network, you are totally hosed. You will still need an either pre-paid plan or pay-as-you-go voice plan as a backup, which are much more expensive.