These discussions of self-publishing tend to ignore a major alternative to the lulu.com type outfits...which is to really, actually publish your own book. By which I mean you write it, design it, make it ready, pay a printer to print it, then market it and sell it.
There are two disadvantages of doing this, compared to the POD route. The main one is that you have to spring for a large print run in order to bring your price per copy down. So instead of paying a few hundred to lulu as set up, then paying them their (really high) price per copy as demand warrants, you end up shelling out a few thousand dollars up front, taking delivery of a huge bundle of books, then have to figure out how to get rid of them without losing your shorts.
The other disadvantage is minor: you don't get their promotional website support, online store, etc. And you have to get an ISBN if you want into bookstores and amazon.com, etc.
Taking the first objection first, there are ways to creep around it. One of my self-published books was a dictionary of specialized slang. I ran the pages off on photocopy machines, had single color covers printed on colored card stock, bound them and saddle-stitched (stapled) them myself. COst was 50 cents a copy (nowadays they would cost around a dollar). But the important thing was...no minimum. I established the popularity of the book, then went to longer runs.
When I set up my eBay store, I went to a small job printer/copier shop and got 2000 copies for around $750. (I made a profit on the shipping/handling costs alone)
Let me point out that the nature of the book was consistent with this format: try to imagine somebody creating the first Klinon dictionary/Star Trek lexicon and selling it at cons. Nobody cares about perfect binding or hologram cover art...they want the information.
Much non-fiction informational books are the same way. Novels are to big to saddle stitch, but if they fall into the right niches, people will buy them for the read, not the frills. Especially since they are priced between five and ten dollars.
Most writers magazines (and certainly google) list big job printers who will price runs of books. If a book has proven it's sales potential and you have a few thousand dollars to invest you can present a fairly professional package at a reasonable price.
As far as the second matter goes, it is now possible to buy individual ISBN's over the internet. Ta da!!! And there has never been a time when mass marketing is so easy and accesible. With an eBay store and a PayPal account you are in business. Set up a web site or page to sel the book, link the Buy Now Or I'll Kill You button to your eBay store and you're ready to sell. And you will be netting over 95 percent of the cover price, not the pittance you get from POD or the 12-15 % royalty from standard publishers. You travel the web posting links to your website and extolling your book. You swap links with pertinent sites. You learn internet promotion kung fu.
And you go around and make bookstore owners miserable. And sell at cons and swapmeets and in the metro.
If it works, you consider pulishing other writers as well and some day you might BE a traditional publisher and get pestered by unwashed writers swarming your for publication like urchins out of Dickens.
Let me hasten to say again: this is an alternative method and neither for every writer not for every book.
But it's a tool that has worked well for many writers and it's good to think about.