I have an awesome plan and I only play $40/mth + tax for it. It's for both voice and data. My contract ends in August and I would like to upgrade to an iPhone (my BlackBerry just died on me) and I'm willing to renew for another 3 years. What should I tell the retention department??? What's the best way to approach this?

I don't want to pay more for my plan and just want to keep it the way it is.