Different companies offer different rates, so shop around. If there is a specific country you will be calling, investigate which companies offer the best rates. Calling a landline is much less expensive than calling a mobile.
Phones are usually purchased from electronic shops or from provider shops with a plan.
There are numerous types of mobile telephone subscription. Different deals and offers are made at different times in the year and subscriptions are usually taken out for a duration of 12 or 24 months. Subscriptions are usually extended automatically without written cancellation.
There are also prepaid offers available. These do not require a subscription and offer greater flexibility, but higher per minute prices. These are offered by most providers, or can be purchased from second-hand shops and or EasyExpat's classifieds.