Back in the day (circa 2003) when these models were abundant on every brick and mortar and online model store, there were times when sellers just wanted to offload them to make way for new models, thus heavily discounting them. The cheapest I've paid for a brand new Autoart model was $30 + shipping, but that was more than a decade ago.

Models sell and eventually make their way to collector's cabinets, manufacturers stop making them due to less demand, then you have ever rising prices of newer models due rising standards of living in China, inflation and what have you. You eventually get to the prices that you see on evilBay and other places.