You need a wallet to make purchases using your phone (i.e. a wallet with its own address to transfer from or to). It's just like carrying cash. I can't transfer

You need a wallet to make purchases using your phone (i.e. a wallet with its own address to transfer from or to). It's just like carrying cash. I can't transfer cash from home once I'm at the store, I need it right there. So what I do is usually transfer some bitcoin from my "main wallet" to my "phone wallet" when I think I might need it. If there are no wallet's for the iPhone, however (I use Android so I have no idea if this is actually true), then bitcoin on the go is useless to me.