That is a hell of a lot of money to be asking for an early 70s dryer. Granted, it has a fluorescent light, but still. I guess the fact that a flea market is selling it explains the price strategy.
We owned this dryer for about 4 years. It was, by far, the fastest, most accurate dryer I've ever used. Probably not worth 100 dollars now, but if it's in good condition, not that far off.
The matching washer, which I picked out, a wonderful appliance with lots of bells and whistles (best bleach and fabric softener dispensers, and a cool powdered detergent gizmo) to beat the band, was a disappointment. Mostly because of the badly designed Straight-8 Activator and a spline that wasn't well installed so the machine "squawked" loudly during agitation. It replaced a 1958 Unimatic so the spin was lame compared to its predecessor as well.
If it is in good condition and runs that is not a bad price, as Doug said $100 is not much money anymore, LOL.
These dryers were workhouses , but small on capacity and HOT running even on low heat, and they are not a good candidate if you have a long vent system.