This is a question I am often asked, (as would Ken).
The answer to this question depends on who you ask and their experience in the ebook business.
For example if you asked Corey Rudl, who is considered by many to be the Internet's most famous marketer and holds the record for the top selling e-book "Car Secrets revealed" for over four years and earns a claimed US$2,600,000 per year... he'll say
he sells thousands.
On the other hand... Someone just starting out, may only sell a few a week and progress from there.
Thus people sell from Zero to 1000's.
However, I can tell you that the number of ebooks people actually sell is directly proportional to the following factors;
1. The amount of marketing and promotion they devote on an on-going basis and the success of those efforts.
2. The subject matter of their ebook... Is it a popular topic or is it aimed at a smaller niche market.
3. Their ability at writing good sales copy.
4. The selling price... Is it priced to sell volume or only in smaller numbers.
5. How well their Web site is geared to making the sale
6. How famous the Author is (Is she a known expert in her field)
7. How good the ebook is (content wise. Does it provide valuable information (Word travels faster than you can blink on the Internet if the product is of low quality).
There are many other variables in the equation of course, but these are the important ones.
If you are wondering whether or not there is money to be made in the ebook business, consider this... There are over 50,000 manuscripts produced each year, of which only 5% get published in the traditional matter. The rest either sit in someone's attic gathering dust or are "self published" by the authors. Many in electronic format. Mark Twain, Zane Grey, Upton Sinclair, Carl Sandburg, Edgar Rice Burroughs, George Bernard Shaw, Edgar Allen Poe, Rudyard Kipling, Henry David Thoreau, Walt Whitman, Robert Ringer, Spencer Johnson - all were self-publishers. You can be, too!
And if you want to be one of the successful ebook self publishers then I recommend you purchase and read Ken's
excellent "Ebook Secrets" .... definitely worth every red cent!
I hope this has shed some light on this issue.
Author of the e-book / CD-rom
"How to earn a good income from the Internet in just 14 days"