Foreigners Foreigners stealing from America!! Internet Ibadan, Internet

I was selling a laptop on Craigslist when I received a normal email inquiring about it. The odd part was they could not pick it up because they were out of state. They wanted to purchase the laptop through paypal and asked me to ship it. No problem! Well she had sent another email saying they sent the money for me to check my email and to ship the laptop. The things that caught my attention was she was no longer a she, but a he instead. Then I had to ship it to Nigeria!!! I checked the email and it was "from paypal" claiming he had paid and I would receive the cash immediately in my paypal as soon as I typed in the track number from the shipment. Well paypal doesnt make you do that, what is going on? Come to find out the whole email was a scam to get me to ship it without them paying! I'm warning anyone to not do any type of business outside of the country!!! I'm seeing tons of scams going on as far as Canada and other countries. I know their another country but somehow they need to be stopped!