I visit antique shops/malls and large flea markets often. In the vast majority of cases, the prices for vintage trains are a joke. However, they expose the public to toy trains, so one purchase may lead to a lifetime hobby. I that case, it was money well spent.
I've purchased a lot of "stuff" from these places over the years, but not trains...although I did get a nice pre-war Lionel "O" set at a church sale cheap.