Read this tip to make your life smarter, better, faster and wiser. LifeTips is the place to go when you need to know about Vanity/Subsidy and other Self Publishing topics.
Subsidy presses exist by deceiving authors into believing they are "self-publishing" when in fact they are not. Self publishing your own book implies that you, yourself are the publisher. If you use a subsidy press (or vanity press), they are the book publishing company, not you. If you want to self publish, you need to buy a set of ISBN's from RR Bowker (not anyone else).