Using apple iphone 4s with a Wi-Fi?

Have an iphone 4s that is unlocked. I live in an area that does not have great coverage other than verizon, which does not sell sim cards. Someone told me that you can use the iphone using our Wi-Fi system. Is this true and how.

You can use Wi-Fi at your house to use internet, but you will still need a carrier to make calls

The Wi-Fi will only allow you to connect to the web on your iPhone (apps, itunes, safari), but it won't allow you to send or receive calls or texts.

Well yea the iPhone could be used on Wi-Fi but that's not gonna help when it comes to calls/texts. You would need a carrier to provide that.