Those Vornado reversible fans come up from time to time on Ebay. They usually are less than $50.00 or so. They do move some serious air. My parents put theirs in the upstairs hallway window. When you opened the bedroom windows you'd get a very comfortable breeze blowing in. Sometime during the night you'd have to get up and shut it off as the house got cold.
The fan my parents had was a three speed, but there are two speed variants too.
It seems the three speed versions have the fan control on the lower right hand side of the fan while the two speeds have the control where it is in the photo I supplied. And the control is a rotary type with a knob rather than a toggle switch. Also there is a nice sized oiling port on the motor for easy lubrication. My Dad used to put 3 in 1 oil in it periodically.