Firstly we will need to visit marketplaces that specialize in the trading of websites. This is pretty easy as there are a few to be found online. Most of these trading websites actually do both the transactions of buying and selling. When buying a website online you will need to know a few things about the website you are thinking of buying.
A good background report, not to mention a health report, (audit report) how many subscribers does it have per month, how much traffic per month. What is the revenue turnover per month? Has the website ever had google penalties, how many backlinks and are they genuine? All this is to be taken into account before you buy. If you have ever had a website in the past it will be second nature to check these reports as you will have done it before as a matter of maintenance of your website.
To look towards the marketplace that will be selling you a website you will need to know what are their commission policies and do they have after sales support. If you are someone who knows nothing about websites it is a good idea to be able to obtain some kind of support once you have bought your website. Websites look like they can be easily managed but do not be deceived by looks.
Some More Popular Marketplaces for Buying/Selling Websites