With all due respect to dbiz, I think he said he's a kid right out of high school. I would think 1,100 bucks is pretty steep. Flights to CR are 300 bucks and you should be able to find a nice place to stay where you'll meet lots of young people for like 15-20 bucks a night. If he's got $1,000 bucks I bet he could last two months if he's resourceful. While it sounds ok to me now at age 40, at that age, I think I would have hated an all inclusive resort and really wanted to experience things a little more. Like meeting the locals. And female Swedish backpackers. That sort of thing.
Awesome man! I did the same things when I graduated HS (except I didn't know how to surf). Never been, but Costa Rica sounds the best to me. I got to Oahu for $400 and spent a month backpacking around there for $800, which was definitely one of the best experiences of my life despite the quality of me and my buddies' cooking. Friendliest bunch of people there ever Hope it goes well!