What's a good option for getting a solid opinion on if the book is great or unreadable rubbish?
As a fairly poor person, what are my options editing wise? I'm hopeless at proof reading my own work.
Try critiquecircle.com -- these aren't experts on whether a piece of writing is publishable, but they're other writers trying to hone their craft. If you get critiques where people say they can't find many flaws, you're ready for the next step.
Try using the Windows Narrator to read it out loud to you. I catch things all the time with my ears that I missed with my eyes.