The values stated in this guide are to be used only as a guide. Values are not set to determine prices as auction and dealer values vary greatly and are affected by demand and condition. The author does not assume responsibility for any losses that are the result of consulting this guide.
Nutty Mads were first produced by the Marx Company in 1963 with the first series and was likely inspired by Ed Big Daddy Roth, Basil Wolveton and Don Martin. made from injection-molded polymer plastic and produced in several different colors. All had the Marx signature molded in the bottom of each. In later years the pieces were reproduced in Mexico and did not have the Marx signature on the bottom and the quality was far less than the originals. Value depends on the condition and series model with the third series being the most sought after and therefore the most expensive.
Their popularity led Marx to expand the product line with several similar series, including Weird-Ohs, Blame-Its and Cartoon Soldiers (commonly referred to as "Nutty Generals"). So if you see Nutty Mads advertised on eBay remember the Weid-oh, BLame its and the generals came after the original 1, 2, and 3 series.
Signatures for Nutty Mads

Series 1:
Roddy the Hot Rod (racer)
Manny the Reckless Mariner
Waldo the Weightlifter
Rocco the Champ (boxer)
Dippy the Deep Diver (Scuba diver)
Donald the Demon (racer)

Series 2:
All-Heart Hogan (policeman)
Bull Pen Boo Boo (baseball pitcher)
Chief Lost Teepee (Native American)
End Zone (football player)
Suburban Sidney (tricyclist)
The Thinker (Rodin sculpture parody)

Series 3:
Smokey Sam (firefighter)
U.S. Male (mail carrier)
Gutterball Annie (bowler)
Hippo Crit (physician)
Mudder (homemaker)
Now! Children (school teacher)

Weird-Ohs: (A similar Marx-produced series of plastic figures, based on the  Hawk Model kits created by illustrator and cartoonist Bill Campbell.[1])
Drag Hag (racer)
Daddy (the Swingin' Suburbanite - racer)
Endsville Eddie (racer)
Freddy Flameout (test pilot)
Davey (the Psycho Cyclist - outlaw biker)
Digger (racer)

Blame it series
I didn't paint it
I didn't eat it
I didn't do it