There are two different systems for mobile phones in Canada; CDMA and GSM, and they operate in the 800, 850 and 1900 MHz frequency range. That said, if you bring your foreign phone into Canada, it might not work in the Canadian Network.
The wireless/cell phone provider available in your area may depend on who has a license in the province where you live.
The following is a list of the largest mobile carriers in Canada:
Bell Mobility: Ontario & Quebec (CDMA)
Rogers / Fido-Microcell: Ontario & Quebec (GSM)
Telus Mobility: Alberta, British Columbia, Ontario, Quebec (CDMA)
Virgin Mobile: Ontario (CDMA-PCS)
Sprint Canada: Ontario, Quebec (GSM or CDMA depending on the region)
Aliant: Nova Scotia, New Brunswick, PEI, and Newfoundland & Labrador (CDMA)
SaskTel: Saskatchewan (CDMA)
If you come from Europe and want to keep your phone in Canada, you may need to go with the only GSM operators in the country, but still need to verify the following:
If your phone is of a different frequency, chances are it will not be of much use in Canada. Unlike in Europe, it is quite hard to find places to unlock phones to enable them working with another operator, so consider getting this done in your home country. If you are lucky and your European phone is unlocked and can read the Canadian frequencies, you can buy a SIM card from Rogers, Fido and Sprint Canada for about CAD $20 and you will be set to go. Note that SIM cards usually come empty and you will have to refill them with a prepaid card or get a monthly service that will enable you to use it.
Prices on new phones differ greatly depending on the retailer and the mobile operator. Prices are usually the same whether or not you buy it through each operator’s outlet or at a retail store.