I just finished a blog tour - that cost me nothing except time spent in interviews and blog posts. No giveaways were involved, though some of the bloggers ran contests in conjunction that had nothing to do with me or my book.
The deals Wal-Mart makes are not author-driven. Publishers have had to bow to the giant retailers like Wal-Mart- still another reason the BIG Five are loath to take a chance with unestablished writers, since their bottom lines have been hurt seriously in recent years. I have yet to see a current bestseller offered with deep discounts, but maybe they exist. Anyway, my publisher sets the price without my input, anyway, so even if I wanted to boost sales - and thus ranking - by offering deep discounts, I couldn't. I did do a Riffle promotion after getting permission from my previous publisher, and this did result in a big sales uptick, so there's no question it works. But I still think it's gaming the system. Not as blatant as getting PACs to buy thousands of copies of a politician's book to get on the NYT bestseller list, but it does use the system that's in place to manipulate ranking. Gaming, manipulating, marketing, what's in a name?
Anyway, a self-published author can do more to "market" in this way, and I've got no objection, other than my above concern that the practice will tend to devalue the output of indie authors. If you can find me an example of a new Coben, Child, DeMille, Connelly, Sandford et al e-book being offered for 99 cents, please let me know, and I'll download forthwith!
Indie musicians are seeing their work offered for free or almost so all the time, and this new streaming venture by Apple will likely make this worse. Michael Smerconish had a guest on his Sirius radio show last week (I can't recall his name) who was touted as being an expert of the iTunes world. Smerconish said, "That sounds great. But how do the musicians get paid?" He asked this question at least three times and never did get a satisfctory answer.
Bottom line, if it works for what you want to get out of the bookselling business, by all means do it. But if landing a top literary agent and then a contract with HarperCollins is one's goal, giving away and selling for 99 cents thousands of books is not likely to accomplish it, Amazon ranking notwithstanding.