Unfortunately, the publishing model doesn't work like this. You are right on the quantity, though; if a locally-published book shifts 10,000 units it is considered a solid seller. But publishers and distributors work in wholesale terms - they receive 90 per cent of wholesale revenue - and authors receive 10 per cent of wholesale sales if the book recovers its costs. If you see a book retailing for $30, generally speaking the outlet has paid $15 for it and, furthermore, they can return any unsold units. If you do the maths, once costs have been recovered, an author can expect $1.50 in royalties for a book retailing for $30.
