I can't tell from the pics if it's a pre-Raleigh(1960) or not but $150 seems awfully high.
Don't worry; the experts should be here shortly.
In the meantime, check out the rear hub. There should be a date stamped on it. I believe the older ones had it right below the name or maybe to the left. I don't see the Sturmey-Archer gear shifter on the handlebars. Is there a little chain attached to the right side of the rear hub, possibly a cable attached to that and running along the frame?
Can you read Nottingham anywhere on the frame or below the Hercules on the headbadge or seattube? If so, then it's a Raleigh and definitely not worth $150.
The bike is also missing the chainguard.
Hercules
A division of B.C.C. until merged with Raleigh as part of the TI takeover in 1960, Hercules was a major competitor of Raleigh, with a strong sporting image. They sponsored popular racers, most partiuclarly Ken Joy and Eileen Sheridan. Hercules made their own 3-speed hubs, which were pretty-much identical to the older Sturmey-Archer AW. Hercules hubs continued to use threaded drivers long after Stumrmey-Archer abandoned them.
Raleigh-built "AMF-Hercules" models are fairly common. They were distributed by AMF (American Machine & Foundry.)
Somebody restored their Hercules
http://www.madeinbirmingham.org/hercules.htm