It isn't so hard, make sure to find a deal here in service selection with someone willing to trade bitcoins for PayPal, add money on your PayPal account, buy the bitcoins to the member with escrow of course. I've never done so since I didn't need to, but it seems that there is quite a bunch of people doing it.
I would never recommend purchasing/selling Bitcoin for PayPal. There are a lot of scammers around here and they will try to reverse the payment after 10, 20 or even 40 days. There are a lot of other easier options, such as Skrill, Bank Transfer and SWIFT transfer. But I would say that Paypal and Bitcoin makes a very dangerous combination.