I flip websites as for a living. I average around 12k a month in sales using several different channels of sales. Flippa is great, on the other hand, I roll with established sites, spurce them up and resell. I own several sites with at least 10k visitors a month, all of which I had purchased and resold.
Personally, flipping websites is not easy, and if you are good, expect to make some damn good money. However, expect to get screwed several times, and always use escrow for your transactions. Make sure you understand the basics of selling, and what attracts the buyer, and what doesn't... Good luck to all!