With so many Americans unemployed, it's no surprise that unscrupulous scammers are trying to exploit their desperation. And thousands are taking the bait. Those concerned about being ensnared by a con should be vigilant, says jobs expert Jeff Taylor, quoted by CNBC. "Watch out for people requesting things out of the ordinary," like your mother's maiden name or social security number. "And no legitimate organization will ask for money up front in exchange for a job." Here, five of the most popular scams:

1. The rebate-processing con
Like many, this scam takes advantage of people's desire to work from home, says the Los Angeles Times. Con artists email job-seekers telling them they can earn over $200 a day processing manufacturer rebates. The catch: After would-be freelancers pay $197 for a compulsory how-to guide, the guide never arrives and the victim never hears from the company again.

2. Secret shopper scams
It sounds too good to be true — being hired simply to shop, ostensibly to report back to manufacturers on how their products are displayed and sold — and that's because it's a con. The state of Los Angeles took action against a fraudster who juiced 80,000 job seekers for $6.1 million by asking them to pay for unnecessary certification for non-existent secret shopper (and bartending) jobs.

3. Foreclosed home inspectors
Ex-NBA star Jay Vincent faces jail for allegedly testing, certifying, and employing people to inspect homes foreclosed upon by banks, reports ESPN. Would-be inspectors were asked to pay $149 for liability insurance and $89 for background checks — after which they never heard from the company again. Vincent and his partner pleaded guilty to fraud and tax charges, and will be sentenced next year. Up to 20,000 people may have been duped by his scam, say prosecutors.

4. The "payroll clerk" scam
In this reverse scam, the swindlers offer their targets a payroll-clerk job, then send the victim a large check to cash. After the "mark" cashes the check, he's asked to wire a percentage of the money back to the fraudsters — to cover "tax" or "insurance." Of course, the check is fake, and the money being wired back is the victim's own. Reportedly, Russian con men have been using online job-seeking websites to find victims.

5. Paying for acting opportunities
Scammers in starstruck Los Angeles are extracting money from out-of-work actors by charging them to audition for non-existent roles. The city attorney's office recently mandated that talent representatives can only charge commissions if actors win a role, and not take money beforehand. "Nobody should be paying for an audition or job interview," deputy city attorney Mark Lambert told the Los Angeles Times

Sources: Los Angeles Times, CNBC, USA Today, ESPN