Flippa is usually good
Definitely a scam. This one is quite common. The sales may well be legitimate (so can be proven through Paypal) but are not from this site. The owner probably has a ton of these.
My advice would be not to buy a site at the moment. Keep doing what you are doing as it's clearly already working.
If you want a legitimate site making $2k a month, expect to pay around $50k. You will not find any "really good deals" on Flippa.