I’m not quite sure how she does it, but PDF-hunting wunderkind raijap has tracked down an interesting tidbit: an official document from the Center for Cinematography in Morocco, listing the productions spends of all significant projects filmed in Morocco in 2009. Of interest, of course, is the listing for Game of Thrones, which gives the spend as 2.7 million dirham (approxmately $320,000 USD). Of course, one supposes this figure relates purely to the hire of crew, extras, lots, and so on incurred in Morocco specifically, and may not cover the budget for foreign actors such as Jason Momoa, Tamzin Merchant, Iain Glen, or Ian McNeice.
This figure is—to my admittedly-amateur knowledge of such things—surprisingly lower than one would have expected, but may help to explain part of the reason filming will once more take place in Morocco (the other being, doubtless, the need to reshoot many of the Daenerys scenes following recasting of the role.)
Another noticeable piece, the naming of Dune Films as the local production company contracted to facilitate shooting. Dune Films has extensive credits, including having participated in the production of Kingdom of Heaven, Prince of Persia, and the soon to be released Inception.