How much did it cost me? Actually nothing in dollar terms. The beta reading and critique group were free (although I had to critique in return to "pay" for the group's services). The line-editing was a barter service, so that didn't cost me any money either.
See, it doesn't have to cost a lot to get good editorial guidance. The critiques in return did take some time, but it actually helped me as a writer. Nothing teaches you your craft faster than critiquing others.
The next book is going through a similar process. I've done the beta readers and critique group, and now I'm working with all the comments. My rewrite this time is less intense because it's a better story than the first one, and I learned a lot through writing and editing Haunted Vampire.
If you're thinking about self-publishing your own book, don't think you can't turn out a polished product without spending a fortune. You can!