Back in 2009 a certain already well-known and well-respected science fiction writer got a considerable amount of press when he signed a million-pound deal with Victor Gollancz.
Contrary to the impression given in the media (especially by way of shows like the contemptible Castle), few writers ever get close to a seven-figure deal.
Still, that million pounds was not for one book, but ten, which translates to a hundred thousand pounds per book - still a figure far out of reach for all but an infinitesimal share of those aspiring to write a novel, but not so large as to be newsworthy. Not only has many a first-time novelist commanded larger sums, but the biggest names routinely command sums orders of magnitude higher (especially when their work has been turned into profitable television shows and films).
Of course, as I have often noted, hard science fiction and space opera, as a small part of the market, carry more modest expectations. Still, the oohs and ahhs at the number reflected a profound misunderstanding of the situation (to which some who should have known better were prey). For this a worthwhile corrective is Charles Stross' parsing of the matter, a response to his having made a recent, similarly more-glamorous-looking-than-it-really-is deal - apparently, for a sequel trilogy to the six-book Merchant Princes saga (reviewed here), which he demystifies in a recent blog entry.
Actual Data on SF and Fantasy Publishing