I've run across many scams on craigslist, one of which involves scammers pretending to be some type of payment processor, needing your help.

They often claim to be a foreign bank, needing help processing payments.  They then send you worthless and fruadulent checks.   They are hoping that you'll be foolish enough to buy into the scam.   I had one send me a check, and state I could keep a portion and then send the rest on via western union.

They hope you'll be naive enough to send your own funds on, and be stuck with the worthless checks.