Indeed, as Daniel said, you can keep your plan. I just did. I bought a new Nexus 5 on one of the special offers. The Nexus 5 takes a micro SIM and so they did have to give me a new SIM card (http://en.wikipedia.org/wiki/Subscrib...). But they just transfer your account to the new card. They didn't charge me for the new SIM card but if you need to buy a new one for any reason I think the cost is $10 plus tax.