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.
Depends on the book and also where I’m buying it from. If I’m going to my local bookstore, I’m more willing to spend money because it means supporting a small business