Costa Rica is beautiful! That's a great price for a fare from Canada. Is it a nonstop? We paid about $250 USD out of Detroit to San Jose, which was a bit of a hassle (the city was nearly shut down by a snowstorm the day before our flight), but the fares from Toronto were almost 3x as much. We connected in Atlanta, which wasn't bad, but nonstops would have been much easier.
I'd highly recommend visiting Costa Rica if you can. Hotels are reasonably priced, and if you eat like the locals, so is food. The weather is beautiful and you can't beat the scenery and wildlife.