Having sat on both sides of the hiring table several times, I can't endorse what FD suggested strongly enough. If you want to spend money on preparations, get some interview coaching. Interview well, and you can turn in soiled toilet paper for a resume and you'll get hired (well, maybe not quite that far, but you get the idea). We had loads of applicants with all kinds of backgrounds. Degrees and certifications mattered least of all. Of course, experience mattered most, and you have already stated that you lack that, but references were good, and personal contact was invaluable.

Having said that, let me emphasize something else that FD alluded to: Speak to the decision maker. HR departments might be your friend once you are hired, but they are your enemy up until that time. I can tell you of a personal case where I hired a guy with zero experience in the job I was hiring, even though he had been filtered out by a lower layer. I had heard from a friend of mine who told me not to pass him over, so I overruled HR and interviewed him. He worked for me for several years and we're still friends, though we have both gone on to different jobs.

Get past HR and get to the manager. If that is impossible at company X, go to company Y. Not only is experience FAR more valuable than certifications, you get paid for experience, whereas you pay for certification.