Wi-Fi is just about everywhere these days, so why do you still have to pay an arm and a leg for pricey 3G and 4G wireless data service from a carrier if you want to get online from your smartphone?

This is a very good question. Now that every smartphone on the market comes with Wi-Fi capability built-in, some frugal wireless customers are wondering whether they can subscribe to a voice-only service and use Wi-Fi instead of a costly data plan to access the Internet.