So are you trying to save fees by going outside poshmark to sell? If so, you've come to the wrong place for support for that!
As for PP, it's not Paypal she wants to use but you're looking for a Friends and family payment, right?
That's unethical for you as a seller and unsafe for her as a buyer.
And by doing F&F, you will NOT get the "okay to ship" statement so you'll lose seller protection too.
Seriously, is saving 3% fee worth it? Not only do you both lose protection but you both don't make yourselves appear to be moral and ethical poshmark users.
Here's a novel idea: Why not have both you and your buyer be honest, pay for the transaction through Paypal either through Poshmark or for good and services, you pay the fees and both you and the buyer will be protected as long as you both follow protocol.
JMHO.