Good luck, Boomer! I noticed you said at one point that there is so much to read up on, which is so true - it feels a little overwhelming this first time around, doesn't it? At least for those of us who actually want to be informed. :)
I don't know your exact financial situation aside from that you're using Medicaid, but I wonder if maybe an option for you would be to find a homebirth midwife who was willing to just do some prenatal visits with you. Our midwives divide up their charges into prenatal care ($1500) and the birth itself ($2500). This is Seattle, which is often more expensive than many other places in the country, but I imagine it's possible many midwives consider the actual birth to be the most expensive part. Our insurance actually covers office visits with our midwives, but not the home birth part (we are just lucky enough to be able to afford paying out of pocket for it). I have no idea how Medicaid works like this, but I wonder if 1) it's possible it might cover your prenatal care with a homebirth midwife, even if you have the baby in a hospital, or 2) maybe you could find a homebirth midwife who was willing to charge you a slow/sliding-scale fee for at least a few prenatal appointments, so you could go see someone who would actually spend time with you and give you a better opportunity to be informed. You could schedule them before your regular doctor's appointment, so that you could essentially go in to those already knowing what you needed to know (or skip them entirely?), and feeling more confident in declining tests you don't want.
I have no idea if that would help you, but for my personality, it definitely helps me to be able to talk things over with someone who is knowledgeable and who I trust.