Prepaid means that you do not sign a contract with a telecommunications provider, but rather pay for prepaid cards, which are basically cellular minutes that you pay upfront, use up, then reload. The minutes that you use are often called “airtime”.

Prepaid cards are sold at various places and are also available in vending machines. But you need a SIM card that matches the network provider of the prepaid cards, otherwise they will not work. For this reason, some people have a number of SIM cards but then obviously have different numbers.

The advantageous thing about prepaid is you are not bound to a contract or a monthly subscription – you pay as you go, as you need, and as you have funds. There are no hidden costs and no suprise bills at the end of the month.

Originally, the Motorola Razor (RAZR) V3 phones were available mainly through AT&T, as well as T-Mobile, Metro PCS and Verizon Wireless. Now, however, the V3 can be made available as an 'unlocked' phone, which means that it isn't locked to any single service provider – a user can get any SIM card from any carrier and use it in the phone.

Razor prepaid cell phones therefore can be used with any network carrier of your choice, but you do need to be careful. Most Razor V3 phones are GSM quad-band with the exception of the V3c and V3m models, which support CDMA.

What is GSM and CDMA?

Basically, these are two different cellular technologies which are not compatible with each other.
Each carrier in the US uses one of these two types of technologies, with CDMA being the most popular in the past. However, GSM has made big inroads into the US and many of the larger US cellular carriers are now GSM.

In practical terms, this means that even if you buy an unlocked Razor prepaid cell phone you will not be able to use it on absolutely every carrier. If you buy a GSM Razor then you can only use it on GSM networks, and if you buy a CDMA Razor (the V3m or V3c) then you can only use it on CDMA networks. This limits your choices only a little, though. GSM is more popular in Europe and Africa, while CDMA has been more popular in Asia so if you intend to do a lot of travelling with your Razor prepaid phone you should bear this in mind.

Other advantages of prepaid

As mentioned, the Razor is a quad-band phone (besides the V3xx) which means that it works in most networks across the world. If you buy a Razor prepaid cell phone, then you don't have to worry about sticking to a particular network provider abroad either but can rather buy a SIM card and top up when you get to the country of your choice. Of course, this means that your number may be different when you're abroad but you could easily let those who need to know what your new number is. Fortunately, the Razor has great messaging options so you could also use IM, email or SMS to let others know what your number in your visiting country will be.