Yep, the bait is to advertise something cheap and it tempts hundreds of people. All they need is to trick a small percentage of people who show interest and they are laughing.
I had a similar thing when looking at a motorhome in Gumtree. Advertised for £7k when it was worth nearer £20k and he would drive it down from Cardiff if I wanted it.
You said the car was £5,000, but how much they really go for?