Thanks for the wonderful responses.

I checked around, and the cheapest place I've found so far is at one of the optical shops in City Center: 230 QR for regular CR-39 lenses for average strength (nothing special added other than the normal coatings). Some other shops quoted 280 QR for the same, and a few did quote 450 QR.

I will try Lulu or Doha Jadeed.

acchabaccha: Let me see if I can match your "low-cost" scenario: 1) Get an eye exam (with pupillary distance measurement for 30 QR. 2) If the optometrist refuses to give you the pupillary distance measurement without your commitment to purchase lenses, go online, figure out how to do it yourself, spend an hour taking many measurements to figure out the most accurate measurement, and then purchase lenses from a supplier in China for 30 USD inclusive of shipping to Qatar.

I have vetted one China source that I believe can provide the same quality that is sold here for 230 QR.