I like to get my hands on the cheapest edition I can in the best condition at that price. If the words in the book are the same as a more expensive one, I’m getting a better value, in my opinion. Then if it’s a story that becomes really important to me I might consider upgrading to a “nicer” or collectors version, and keep the old ones as lender books.
I’m totally fine with the idea of spending more for a really nice copy, but I prefer reading paperbacks, so my limit usually ends up being $20 if I buy them new.