Whats an acceptable price to sell a legendary parcel to a friend for?

Wondering what the community thinks an acceptable price to sell a legendary parcel for primarily AB wise. We were thinking along the lines of a 500 AB minimum for the sale.

Epics for 250 AB even?

Saw on the AE calculator the total worth and that prompted the discussion of outside AE payment for sale options. Would AE have to be informed of this exchange? The discussion for cash in hand/ paypal came up as well, but I'd like more clarity on that subject if that's even allowed or not? Screenshots of transaction with a note?

I'm at 280 parcels and mostly f2p. I only use gift cards to get AB besides the ads. Just aiming to follow the rules and keep the parcel and badge counts climbing.

Thanks!