Here is something i found on craigslist that actually worked and not a scam! I purchased 2 promotional codes for United (he has Northwest also) of $100 off the purchase price for $20 each. My flight to Denver saved me $160 profit. Here is his email and let him know John C. gave you his email address. Post here if you used and results so others know feedback.
Abraham Kohen <firstname.lastname@example.org
You can use paypal which has fraud protection.