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 only buy hardcovers so my average spend is a little more, but this also serves to limit my spending since I definitely won’t go on ebay and buy like a $100 copy of an out of print hardcover. So while it may be more expensive on average it also gives me a reason to not just go crazy and buy every single book I want to read.