I'll send you a check for $10,000. You deposit the check and keep $3500. Wire me back the $6500 that is over payment and I will contact a "shipping control officer" to collect the merchandise....
You could string along the scammer and have them send the fake check, play up a story on how hard life is and how you have not been able to get the fake check to the bank...etc, etc (see link for ideas on how to scam the scammer: Busted Up Cowgirl
Meet me in person and hand me cash or verified funds check or Paypal me the $$ and I will wait to ship the merch until the Paypal $$ are deposited to my account. Anything else leaves you open to getting scammed.