That set must have been pre-war O scale, or Chicago Flyer, which is what the company is referred to in the years before A.C. Gilbert purchased it. You can read up on the history in the Wikipedia entry: http://en.wikipedia.org/wiki/American_Flyer. I think that set was worth more than $50.
I guess I’m a bit of a rubber-gauger. My main collection is HO, but since being in an apartment I’ve concentrated more on restoring the old Flyer stuff because of the ability to break it down and put it away when necessary. I need a basement again. [sigh]
Heyy guys, I couldnt resist I went down to test out the old power pack plugged it in, took tester thing I use, and light up the bulb really bright, I was suprised it still worked. Took a look at some of my locomotives and discovered some really messed up wiring. I have some pictures of the wires I will post later on to see if anyone can tell me what needs to be fixed. I Knew that these trains would need a decent amount of work, but I was hoping all the trucks would be on =(