Cheaper Air Ticket?

My last trip to Thailand in November 2013 I paid a record high $1500+ dollars. I think It cost me around $1540 CAD. The initial ticket check into this coming trip yields a price of $1224 CAD. How does that work out?? The same airline, the same time of year, two years later and the ticket is over $300 cheaper? This is just a preliminary check the ticket might end up costing more, still it is promising!