Whatever $300 is at bitstamp rate at time of trade for $400 moneypak. Escrow is fine, if used, escrow is the one who adds the code. I will never know the code if escrow is used.
I will beat the offer. I can offer a 25% premium to bitstamp rate (multiply rate by 1.25) and escrow on LocalBitcoins where I have an impeccable reputation.