What I do is use a pre-paid ICE calling card. You can buy them in a ton of places. I usually buy one for 3,000¢ (about $5.75) for 22-24 minutes of calls, no connection/maintenance charges. It's about .25-.30/min.
*When going to buy one ask for "tarjeta telefonica", make sure it says "199" on it, not 197.
If you rent a CR cell phone, all local calls are included, so just
dial 199, enter the PIN, then
dial 00-1-area code-phone number and you're good to go.
Here's what they look like:
http://mysite.verizon.net/orangeCRT/fil ... e_card.jpg