I self published a 5-star book for 1k.

$500 for interior designer who made original maps for each chapter (it's a travel memoir).

$500 for a professional editor... which, was a REALLY friendly price, because they were a good friend who offered about half her normal rate.

I did my own cover design, and I had a "readers group" who read an early draft and gave me notes.

I think there are creative ways to keep the cost down is my point. My book's sold nearly 1000 copies so I've made around 5k from the venture at this point, and now with every sale that number just goes up.

Here's the book if you're curious...

https://www.amazon.com/Not-That-Anyone-Asked-Finding-ebook/dp/B08LG5V4X4