What is the cheapest plan for iPhone? And what for Android?

I have an iphone and my brother have an Android and we want to know what is the cheapest plan.

Depends on a lot of stuff; where you live, company you choose, and what type of service you want for it (texting, talk, internet). Go online and look up the company you have nearby you and you can usually get an estimate at the price it will be. I have an s4 and my boyfriend an s4 active, we have a plan with mobile data, unlimited text/talk and its over at att for 142 dollars a month. If it was just one phone for all of that I mentioned he would only pay 90 something dollars.