Avoid scams/fraud by following these simple rules:
Deal locally and exchange items and money in person - always follow this rule and avoid nearly all scam attempts.
Never pay in advance – most scammers will try to convince you they will ship the items after you pay (in full or a portion of the money). And once you pay, they'll disappear.
Never give your personal or financial information (bank accounts, credit card numbers, social security number, copies of driver's license, personal ID or other documents) to people you never met. If it is about job or housing, meet the interviewer/estate agent before submitting to credit or background checks.
Avoid deals involving WesternUnion, MoneyGram or similar wire services - these services are not meant for payments between strangers and are preferred by scammers.
Avoid deals involving escrow services - scammers may suggest using escrow services to complete the transaction. There are fraudulent escrow websites, they'll take your money and you'll never get what you paid for.
ASNClassifieds does not handle payments, transactions and does not provide "seller certification/approval" or "buyer protection" – anyone who says he is "certified" or that transaction is "guaranteed" is a scammer.
If you are selling, never accept cashier checks - banks will cash them, but will take the money back out of your account and hold you responsible if fraud is discovered later on.