I nearly got scammed about 11 years ago.
I was selling a laptop on eBay and was contacted by someone looking for additional laptops. They were from a foreign country (can't remember where) and they told me they wanted to purchase new laptops from America because in their country the laptops they purchased often had components missing or downgraded.
It seemed plausible and they were basically offering to pay a couple hundred dollars over retail. They wanted to pay with a check and they had a bank account in the US. Nothing came off as fishy - no high pressure sales tactic or anything. I told them I would take a check but would call the bank to make sure funds cleared before sending and they agreed.
I received the check in the mail and deposited it. I called the bank the check was from and they confirmed the check was good and that there were sufficient funds to cover it. I called my bank several days later and they told me the check had cleared and funds were available to withdraw. I ordered the laptops and prepared them for shipment (customs forms, etc.) The day before I was going to ship them I received a call from my bank telling me that the check had been put on hold by the sender. I asked what happened and all they could tell me was that there was a stop payment put on the check. I asked them about our conversation where they confirmed funds were available and withdrawn and apparently that doesn't matter if someone puts a stop payment on the check. I was pretty close to being scammed out of $5K in laptops.
That was back in 2001 or so. This scam was all about timing. The guy did have a bank account in USA, he did pay with one of his own checks, he did have sufficient funds, and he know that he could put a stop payment even after the check was showing as cleared. It was complete bullshit but he knew how to game the system.
Moral: nobody is going to contact you to make a few hundred bucks to sell them some electronics. Scams come in all different forms. If it seems like a scam, it is a scam. If it doesn't seem like a scam, it is still most likely a scam. They get creative - don't be the first one to fall for something creative.