Fast bitcoin load service I'm freelancer and I'm willing to get paid with bitcoins. Hence I need to find some service which allows to top up bitcoin wallet with minimum efforts (even without registration). Something similar to: https://paynow.payoneer.com/ (but for bitcoins). Simplicity is really important.

May anyone suggest some?
There was a great service back in the day called https://www.moneypacket.org/. You can send bitcoin with email. I think it still works so it seems like a great solution to your problem.