I have recently edited and published my mother-in-law's memoirs via Lulu. They are cheap (under �4 per book for my project and yes, you can order as many or as few as you like), the service is good, the product of good quality. Lulu doesn't claim any more than being a basic p.o.d. printer - they will not promise you fame and fortune.
I was able to do my own cover design, editing and typesetting (which isn't difficult), which helped get a more professional-looking product. Bob Trubshaw's "Writing and Publishing Local and Family History Successfully", I found a mine of information here, not so much for the history aspect as the practical stuff. The link:
http://www.hoap.co.uk/general.htm#HoTo
POD companies such as Lulu won't do any marketing for you (other than their own website) unless you pay them, and even if you do, don't expect fame and fortune. Expect to do a great deal of hard work on this side if you want real commercial and/or financial success. Also remember that Lulu are an American company, so most of the marketing will be USA-based.
I have recently completed a novel. I don't have the time or the inclination to wait for publication via the conventional route, and I don't mind if doesn't make anything, so I'm planning to self-publish later this year. I may use Lulu for this, or I may go with DIggory Press - slightly more expensive but they're British, and I've heard good things about them:
http://www.diggorypress.com/