Income claims on Flippa are notorious for being faked.
With that said, I'm not saying that all Flippa income claims are bogus.
You just have to live with the fact that a certain percentage of people that use Flippa will move heaven and earth to fake people out.
You just have to pay attention to all other public metrics that they publish so you can publish with their listing so you can get a clear understanding of the probability that the income claims that they're making are accurate.
Also, it pays to deal only with individuals who have a solid track record of successful sales on Flippa.
You know you are in a tricky situation when you're dealing with somebody who has not got in a sale, who doesn't have much of a history and this person is selling a website that is supposed to be making money month after month.
What other metrics should you pay attention to?
You should pay attention to backlinks, social signals, how much content is on the website.
Pay attention also to Archive's wayback machine.
If you notice that this website just got active very recently, that's a red flag.
Also, if you win the auction, you might want to ask the seller a limited three-day access to verify that this website is actually making money.