It's true that the blackberry has an indigenous messaging service that uses the wireless internet as a kind of MSN messenger service, however even people who subscribe to the blackberry "bolt-on" service with their carrier have difficulty getting the service enabled (specifically o2). It may also not have functionality in that many countries, it really depends on where he is traveling and whether they have 2g/3g/4g coverage there although where it is covered will be free to use (standard data charges only).
Your choice for purchasing your phone is really down to you and how you want to use it.
- Sim free - You pay full RRP for the phone and then have to get a sim card either sim-only contract or pre pay which you will then need to top-up or pay a bill for. Sim-only contracts often have more inclusive calls or texts and no minimum term.
- Subsidised or Free with contract - You pay little or nothing for the phone, and pay a fixed amount each month +any hidden charges e.g. calls not included in your allowance. usual 12-18 month minimum term. Take the cost of the phone and compare it to the monthly charge multiplied by the minimum term, consider what you are getting included for the difference and remember to ask them to throw in a case, they will usuall do this if it means they make a sale.
- Pre-Pay direct from specific carrier - They will have the phone locked + branded to their network for a slight reduction in handset cost, you will still need to buy credit for your phone as you use it.
Personally I dont make many calls or texts so I stick with Prepay as 1months bill will last me 2monhs in prepay credit. High users are often better with a monthly contract but note that international calls are not usually included.