Smart Philippines offers two types of plans - prepaid and postpaid. For prepaid, you simply buy a phone either from Smart or from the open market. If you buy from Smart, the phone typically comes locked but also includes a SIM card. If you buy in the open market, you need to buy a SIM card as well. SIM cards currently sell for Php200. (Exchange rate is about Php54 to USD1. Then you buy prepaid cards containing credits that you load into your phone. When you use up the credits, you buy more prepaid cards to continue using your phone and SIM.
For postpaid plans, you sign up with Smart for a two year contract. You are billed monthly for your usage. Depending on your plan, you usually get a free phone. For the Gold Premium, which requires a minimum monthly consumption of PhP2665 excluding long distance calls, you get a Nokia 4650. For Gold Select, with a minimum monthly consumption of PhP1995, you can choose between Nokia 7210, the Smart Amazing Phone, and Nokia 6100.
Lower plans feature less expensive models. If you subscribe to a lower plan but want a more expensive model, then you can pay the difference. For instance, you can subscribe to the lowest plan, Gold Rave, which has a monthly minimum of PhP500 and pay an additional PhP18,750 to get the Smart Amazing Phone.
I might be wrong but I don't think Smart is making the Smart Amazing Phone available without a plan though.
Hope this helps.