Firstly you must be mad, secondly I think as a non-qatari you can only buy in Westbay Lagoon, The Pearl and the Lusail development.

Starting price for studio (no bedroom) is about QAR 850,000 c. US$ 234,000. Most Bedroomed apartments (2 bed) appear to be QAR 2,000,000+ c. US$ 550,000+. Villas are QAR 7,000,000+