Hello all, question concerning website purchase

Hey everyone, I have been stalking these forums for a while and reading lots of quality information that has helped me very much. However now I have made an account for help with a more specific question that I have. I was searching these forums for anything related to "Flippa scams" and how to tell which ones were bogus. I am not easily fooled and I can spot the websites that are recently created and poorly thrown together and sold for $500-1,000. But I know that many sites are actually legitimate and I came across one I was interested in but I had some concerns and thought I would ask around before making an unwise purchase.

I am not able to post links yet I apologize...

Flippa dot com backslash 2740765-free-file-hosting-free-image-hosting-free-backup-services



I am just very confused as to why I see so many sites for sale for around 1k that claim to take barely any work and make over 1k a month just on ads alone plus the revenue from the paypal screenshots...what is that point of selling a site for the price of what it would make it in less than a month? and especially if it takes no work to maintain. It is a red flag to me. Could someone please breakdown this site for sale and tell me what the PROs and CONs are? I would like to buy an already established site but it all seems so sketchy to me.
Thank you in advance