I booked flight for London from the promotional website of QA.

Once you get the promotion fare, beside the fare you will find a note:

"****Fare shown is 50% off the normal fare per adult.****"

When I checked the normal fare per adult from QatarAirways and other travel agencies (just to reconfirm the normal fare is the same)

Promotional fare is not 50% from the actual fare.

It is much higher and the difference is QR. 275 per ticket.

Also there is a catch. The child ticket will be calculated as per the adult, which I feel is unfair.

That is why I always prefer to travel thru Emirates Airlines :-)