What's the cheapest plan for the Iphone 5?

I'm looking at getting the iphone 5 but am looking for a plan that isn't very expensive per month and the iphone isn't expensive as well. I have a prepaid phone and would like to get an Iphone as I have an ipod to have everything on one device. My family is also looking at getting an Iphone 5 so family plans can be included? What plans have you found to be the cheapest and most reliable? I know it depends on how much I use it but I really don't use it much so I would get the lowest option possible. The problem is I just don't carry around my phone and people can't get a hold of me. I carry around my ipod much more than my phone.

Added (1). Sorry I should have been more clear but the service provider is what I'm looking for. I mean I want all the possible options even prepaid. Is there a website to compare service providers by location or do I have to go each company in my area?

First off what service provider?

The prize for the cheapest iPhone 5 plan definitely goes to Straight Talk. They offer unlimited talk, text and data for $45 a month.

Straight Talk teamed up with Walmart to offer a special refinancing option, which could also be nice. They do not offer a family plan but the individual plans combined would likely be less than what you'd get with the family plan of most other carriers.

Another great fit might be Net10. They offer family plans for 2-4 people. With four people, the price per a person is about $42/month with their Auto-pay program. Net10 also offers the iPhone 5: http://www.net10wirelessphones.com/Apple-iPhone-5-NET10.html

With both prepaid options, you would have to purchase the phones through the carriers to acquire the microSIM needed.