Paraphrasing what I've heard here from people who know:
Although every writer can negotiate with a publisher, typical royalties for an unknown author might be:
Hardcover royalties of 10% on the first 5000 units sold; 12 ½% on the next 5000 units and 15% thereafter. (Hardcover figures are rarely different, even for authors who sell well.) Trade paperback royalties are 7 ½%. Mass market royalties are for 8% for the first 150,000 units sold and 10% thereafter.
First printings for the unknown author lucky enough to get hardbound are typically 5,000 units. Say it sells for $25 (because we sure like our round numbers) and it sells through--all 5,000 copies sell.
$25 x 10% = $2.50 per book in royalties
$2.50 x 5,000 = $12,500--not much considering that it probably took a year to research and write the book, and quite possibly longer. A full time minimum-wage job would earn the author more money.
More often, the unknown author gets trade paperback, the big ones. They’re usually about $15.00
$15 x 7 ½% = $1.12 per book in royalties--not even half what the hardbound earns.
$1.12 x 5,000 = $5,600, not a wage you could live on.
Or maybe the unknown author goes straight to mass market paperback. They’re often about $8.00. Royalties on 5000 copies comes to $3,200.
Of course, if you happen to write the huge novel of the moment, maybe you sell a half million copies.
Of maybe you only sell 2500.
Maryn, who's sold, ah, zero