Being able to pay by Paypal doesn't mean a lot. Scammers have accounts that they can launder money through and then disappear without a trace.
I honestly wouldn't touch this with a 20 foot pole. I guarantee it's a scam.
Firstly, it's written exactly as any Nigerian phone scammer would write and a quick Google finds this guy spamming all over the net.
Secondly, the guy claims to be in the US yet it's obvious that this advert wasn't written by a US citizen. A US person wouldn't sign his name as "Mr Kellin". That's just way too formal for a seller in the West - he'd include his first name and wouldn't use "Mr".
Thirdly, three free email addresses. A proper company would have it's own email address rather than use Yahoo, Hotmail, etc.
And finally, if you Google one of his email addresses -
[email protected] you will find that he was previously using
[email protected]. "lag" almost certainly stands for Lagos, Nigeria. In the Gmail address "Owo" is also a Nigerian town. The scammer has just been too lazy to change it.