Lennydo wrote:
Just look for the "Kolbi" signs right around where the escalator goes down to immigration on the airside when you get off the airplane. Kolbi has set up a kiosk in this area and it will be expanded into a store soon. You can buy a prepaid SIM card valid for 120 days for $20 and they will also setup your phone. If you put $1 or 500 Colones on it prior to the end of 120 days, it will be extended for another 120 days. It includes, voice, text and 3g data. I've had my same CR number now for nearly 2 years.
SIM cards are sold in denominations of $5, $10, and $20. I would only buy the $20 card if you plan to stay a while (2+ weeks) or plan to call to the US a lot. The $5 SIM will give you about 60-70 minutes. That's usually enough for me for a 4-5 day trip.
You can recharge online (from the US too) here:
https://www.grupoice.com/wps/portal/app ... rgaenlineaThe minimum recharge is only ¢100 colones, that's about $0.20.

Quite a hefty price to pay to keep a line active for 4 months.
Lennydo wrote:
All you need is an unlocked & jailbroken GSM quad band phone or one with 850MHz GSM frequency and it should work. If it works on T-Mobile in the US, it will likely work in Costa Rica. I like the older 3g iphones since you can also use Skype to call the US even when you are not around WiFi. AND you can check your US email if you wish.
Just to make it clearer for the novice users, the 850 band that Lenny referenced is the #G band. Regular, non-smartphones, must run on GSM-1800 to work in CR. Smartphones must run on 3g-850 to get internet. I don't believe that smartphones must be jailbroken, just must be unlocked.
Check this:
http://www.worldtimezone.com/gsm.html