This is a good post about Penguin's self-pubbing service, called Book Country (titled "Sucker Country," hee). If you read it, you'll see that Penguin is engaged in a delicate balancing act. It has to imply (but not promise) to newbie writers that they are going to be published by Penguin! OMG!! This is the major leagues!!! At the same time, it has to make sure that Book Country is legally separate, otherwise the authors Penguin publishes and their organizations will say, Oh, Penguin is now just a sleazy scam of a press, I shall take my business elsewhere!
I assume something similar happens when someone hangs up a sign that says "digital publisher" and asks for $3,000 or half your royalties to do more or less what I spent part of an afternoon doing last Friday. They say, Oh, but I'm a PUBLISHER! I'll PUBLISH your book, and then you'll be PUBLISHED!! and the writers, zombie-like, reach for their wallets.
Here's a reality check: It's the pricing schedule for Book Baby, which will produce an e-book for you (and design your cover) if you pay them. I haven't used them, but I know people who have and were happy with the work. More important: File conversion (complete with table of contents!) and distribution is $99, plus a $19 annual fee after the first year. The most-expensive "deluxe" cover design is $279.
Total technophobe? Afraid to do a cover? Don't even want to try doing it yourself? Fine--there's your price range.
When people start asking for five or ten or thirty times that amount of money, you need to become DEEPLY skeptical. They are NOT five or ten or thirty times better. Remember, experienced professionals typically charge you less because they are more efficient and can handle a large volume of work.
And nobody--NOBODY--can promise your book will become a best-seller. NO. BODY. The people who say that they can make that happen are lying to you. The people who hint that they can make that happen are misleading you. The people who want all your money to make that happen...run Penguin. It's sad.
And if you want to spend oodles of money, David Farland details how he's spending approximately $10K to promote his new book here. Note that the money is primarily going to advertising, giveaways, and getting Farland access to other writing platforms--not book production.