Fab progress, Rebekah!
Absolutely don't pay that kind of money to a "self-publishing school"! I've been successfully publishing my own books for over ten years, made enough money from the books to buy our retirement home and renovate it, and spent next to nothing learning how to do it. There's so much information on how to do this available at no cost, and the process is much simpler now than it used to be with lots more options. It's very possible to create and publish a beautiful book with minimal spend.
1. Write the book;
2. Type it up using proper formatting- this is a good guide:
https://kdp.amazon.com/en_US/help/topic/G200645680 Yes, it's Amazon, but the basic formatting works the same for ebooks no matter where you publish and good formatting in the manuscript right from the start will make it way easier to format your paperback. There's also plenty of other good information about self-publishing ebooks and paperbacks on their Kindle Direct Publishing site. Draft2Digital is another useful site with good info -- it's one a lot of authors use to publish ebooks if they don't want to be exclusive to Amazon. The instructions given are usually for Word, but if you don't have access to Word, Google Docs or one of the other free word processors will work fine and cost you nothing;
3. Run a spelling and grammar check;
4. Get people you trust to read it, ideally people who aren't close friends or family members but who do read this sort of book. You need people honest enough to point out typos, what parts of the book worked well for them, what maybe didn't work so well;
5. Consider what changes you might want to make based on the feedback. Always keep backup copies of the previous versions in case you change your mind!
6. Get the book edited. This can be a big expense, but I know plenty of authors who haven't paid for editing, who swap edits with author friends;
7. Think about where you want to publish and sell the book. Ebooks are a big market, so don't ignore that! Read up on the different options for where to publish ebooks, paperbacks, and even audiobooks;
8. Cover design - people will say you can't do your own, and for some people with absolutely zero design sense that's true. But most people do have some feeling for design and can do a decent job of a cover. An important issue is to be sure to only use fonts and images that can be used commercially;
9. Think about how you want to communicate with your readers - social media, newsletter, website? None of these need to cost a lot of money. You can start setting this up before you publish the book;
10. Go ahead and publish the book on your chosen sites following their guidelines.
Pray a lot and enjoy the adventure!