To link your paypal to gcash need mo ng 100php balance sa gcash to link pero ibabalik din yun sa account mo mas madali siguro kung pupunta ka sa Globe Store for assistance pero sakin basta may balance nag link na sya after 24 hours. After mo ma link yun account madali na magamit yun funds mo sa paypal as for me ginagamit ko yun Gcash Card para maka withdraw in any atm machine.
Already linked my paypal to my Gcash, and it doesn't seems that it requires a balance of Php100.00. I just picked the Cash In then select remittance then Paypal, it only requires a verification process with your paypal account. And after that I already claimed and make a withdrawal based on the rates on dollar to peso.
Just withdrawn a $11 and Gcash converted it into Php577, it seems small but I think there are some hidden charges when you Cash In from Paypal to your Gcash Account.