Reserving a micro instance only means that you get discounted usage hourly usage of that instance. You have to pay usage fees on top of that. By my math, 24 hours * 365 days * $.007 per usage hour (VA datacenter) = $61.32 in usage fees. Don't forget the cost of elastic block storage, too, especially if you're going to save snapshots. A full-time micro instance will cost ~$150/yr.
AWS pricing can be complicated, so make sure you read: