[I]f you are going to self-publish, for the love of all that is good and decent in this world, don’t pay to do it. In this day and age, there is no reason to do so...
[This] assumes you are minimally competent to copyedit your own work and are competent to do a basic design for your book, either on your own or using the default settings available on Lulu or other similar services. If not, you can hire people to do these specific tasks, which is still very likely to be cheaper than a suite of services you would buy from a vanity publisher.
In related news, there's been a bit of an online brouhaha surrounding romance publisher Harlequin's announcement that they're launching their own "vanity press" imprint! They got spanked pretty soundly by several trade organizations, including SFWA, and that's all I'm going to say about that!
Always remember Yog's Law: Money flows toward the writer! (And thanks to Viable Paradise's Jim Macdonald for originating that axiom!)