All it took was a little splash of color and Apple has one of the most sought after smartphones in years. In just the first weekend, the company struck gold, selling more than 9 million of its newest versions of the iPhone.

But this gold rush has created a market for people looking to cash in, especially on the gold-colored iPhone 5s.

The 16GB version sells for $ 649 on the Apple website, but it’s back ordered and won’t arrive until mid-October. Do a quick scan of Craigslist and hundreds of ads pop up. While Apple only sells four phones per person to cut down on pricey re-sells, many people claim to have multiple phones for sale – and the gold 5s is going for about double what it you pay in store. For that kind of money you’d expect gold coins to come out of it.

Apparently the opportunity to get gold was too nerve-wracking for one bidder on E-Bay who typed in extra zeros during the bid process, almost paying $ 10,100 for a single gold iPhone. Fortunately, the seller cancelled the bid, by request of the sloppy-fingered buyer. There are many other auctions where the gold phone is going for twice its retail price.

Now comes the cautionary tale of buyer-beware. If something doesn’t look right or sound right – your gut is probably correct. Smartphones have created a spike in robberies over the past year and with the arrival of another hot item, you can expect criminals to be looking for a golden opportunity to strike.

If you do plan to buy an iPhone through eBay or Craigslist, how do you know whether the phone is stolen? Here’s a quick way to check. Each phone has a unique ID number. These numbers are often referred to as IMEI, ESN, or MEID numbers. They’re usually on the back of the phone, or hidden away beneath the phone’s battery, and consist of a 15 digit ID number.

If a phone is reported stolen, that ID number is basically blacklisted, which means you won’t be able to activate it. For eBay or Craigslist, just ask the seller for that number. You can then check with your carrier to see if the phone is on the list. There also multiple websites where you can run a “background check” on the phone, such as Swappa. If you can’t get the I-D from the seller, that’s a red flag right there.

If you get the phone and still have questions, you can get to the ID yourself, by dialing star, pound, zero six, pound. The number will pop up on the screen. Or go to settings, choose general, then about, and scroll down. You will see the “IMEI” number listed.

So it is easy… no I-M-E-I… no deal!

Jennifer Jolly is an Emmy award-winning consumer tech contributor and host of USA TODAY’s digital video show TECH NOW. E-mail her at techcomments@usatoday.com. Follow her on Twitter: @JenniferJolly.