Its a good price but looking at qatarairways.com it seems that despite offering a 'First Promo' fare, none of the aircraft operating CAI-DOH-BKK actually offer a First Class cabin. Despite all the itinerarys listing a First Class fare there's only one itinerary that offers the A380 out of the seven or eight options on the list so choose wisely!
Decent J class fare also though.