Ok. So what is the best to do in situation that i already send money via PayPal, and I suspect that I had been scammed? (Two hours ago he should send BTC.)
Yes, of course, everything is legit.
You can open a dispute in PayPal claiming you did not receive the goods you paid for given that you sent this payment as goods and services.
In case you sent this payment as family & friends then there is nothing much that you can do other than claiming this transaction as unauthorized transaction but chances are very less that you will win the dispute as PayPal will investigate your claim and most probably find nothing unauthorized as part of this payment.