This is actually very simple, people. Leaving aside the actual discussion of the wisdom of self-publishing, generally speaking, if 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.
If you don’t need physical copies of what you’re writing, then there’s especially no reason to pay anyone to publish, since a simple word processing file will suffice, and if you’re truly inspired to put your document into pdf or one of the various e-book formats, there’s software that will let you do that for free.
If you do need a physical copy, then someplace like Lulu.com will let you design and set up that physical copy for free, and the only time you (or anyone else) pays for the thing is when you order a copy, in which case Lulu charges you for the paper, binding, shipping and (I’m sure) a small cut for their profits. This is vastly less expensive than any other way you could do it.
(Bear in mind that the above 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.)
Speaking personally, when it comes to self-publishing, as long as people know what they’re getting into and have their expectations grounded in the real world, I have no problem with people self-publishing, since I’ve done it myself at least a couple of times, and may choose to do it again in the future. I also have no problem with services like Lulu; I have a Lulu account and I use it whenever I finish a manuscript because I run off personal, bound copies for myself and my wife prior to official publication, and occasionally to auction a copy for charity (Lulu also offers “service packages,” which I don’t recommend, but the basic package — which is what I use when I use them — is free). Self-publishing can be useful in certain specific circumstances, even if it is almost never profitable in any significant way.
But again, if there’s one thing I can drill into your head about self-publishing, it is: Don’t pay for it. There are lots of ways to do it that don’t involve you shelling out a dime to anyone else before you have a product available to sell.