With current difficulty, how long its takes to generate the one btc  in 3TH/s rate?  couldn't understand from hash calculator.  Any idea?

It's kind of surprising that people still need educating about Paypal.  I know for a fact they have been stealing money since 2003 as that is when I first had funds frozen by them.  Their policy when your account is suspended is "talk to the hand".  They make some arbitrary decision that your account is tainted, keep the money and refuse to discuss why.  This has been their policy for at least a decade, but muppets continue to sign up and use them.  I am amazed an entrepreneur has not been able to displace them in the market - perhaps bitcoin will assist in this.  If someone can come up with a painless and smooth way to transfer fiat to bitcoin and vica versa, I think they'll make more money than Elon Musk and Satoshi Nakamura combined...

Same issue here.  I can understand restrictions due to high traffic volumes, but it could easily be solved with a membership/donation option.