The 'plan' is determined by the network provider. Since you state it's unlocked, you cna simply obtain a 'pay-and-go' SIM from any service provider. Once the SIM is registered (and topped-up for the first time), your phone is 'good to go'. You don't need to have a contract.
If the net 10 phone is "unlocked" and the sim card fits. Usually the phone needs to be unlocked network wise not pin wise.
An unlocked iPhone 4 can be purchased directly from Apple, and is a legal way to use an iPhone without having to have a cellphone contract. It can be used with a prepaid phone plan, with the caveat that a data plan must still be purchased. One simply inserts a SIM card, which can be obtained from a previous prepaid cellphone or purchased from Amazon, or the cell phone company. It is ideal for those who want an iPhone without the contract.
Yes you can. . . .for example you can put a at&t prepaid go phone SIM into an at&t contract phone and it will still be prepaid.
It is possible to get a prepaid plan that costs less than a contract. It depends on what services you want. If you want internet, it is often cheaper to buy a contract, while simply using minutes to talk is cheaper prepaid.
No. You can purchase the phone unlocked without any service plan, and connect it to any compatible carrier. It doesn't matter if the carrier is prepaid or not.
No, T-Mobile is GSM and Verizon is CDMA so you can't switch between those two networks. Unlocked T-Mobile can be used on AT&T though.
Yes
If I had an contract plan with alltel and i cancelled the contract can i use the phone as a prepaid phone
Yes. As long as you are out of your contract or willing to pay the cancellation fees - you can unlock your phone and bring to a prepaid network. Once you unlock your phone, you just need to purchase a SIM card. I personally did this a few months ago, and switched to Straight Talk. I know there are other prepaid networks that can take unlocked phones as well.
Prepaid is the same as fixed term!
The website cellphones.about.com is the perfect website to answer your question. The website first goes into detailed explanation on whether prepaid, unlocked, or a contract is best for you. Next, they have links to cellphone carriers so you can compare the prices.
Yes T-Mobile has some smartphones available which that you can get with one of their prepaid ( no contract) plans. They cost a little more than the phones you can get with a contract though.