Revenue is one of the most important factors in evaluating a website.
Simply check any applicable revenue method during the listing creation process. Buyers who are interested in that particular monetization method will be shown your listing when they search Flippa.
This can be done in the "Basic Details" portion of your listing draft.
If you select "Yes" to the question "Does your website generate revenue?" then you will be asked to fill further details which include
(a) Average Monthly Revenue
(b) Average Monthly Expenses
Later on within the draft (in the Verify, Revenue & Cost step) you will be required to provide a monthly breakdown over the last 12 months.