So, now that you know a little about how action figures came to be,
MAIL-IN PREMIUMS (or mail-aways):
The concept is to get the consumer to buy other products and send "proof of purchase" seals of those products back to the manufacturer in order to receive the figure which is not available elsewhere.
Kenner is a major culprit of this marketing tactic. Some of their better known mail-ins include: "Boba Fett with rocket firing backpack" (which actually came with the rocket glued in due to child safety regulations), "Ambush Predator", and the more recent Star Wars mail-aways, just to name a few!
A great example of exclusives were Playmates' Kirk & Spock dressed in the garb of a classic Star Trek episode "A Piece of the Action" available at Kay Bee Toy stores. Not only were both these babies exclusives, but limited to 5,000 each and there was absolutely no advertising to even promote them. Talk about an exclusive!
This scenario happened most recently with Playmates' "Slag" from the "WildC.A.T.S" line.
Possibly one of the most sought after variations in some time is Kenner's 1995 "Power of the Force" tan vested "Luke Skywalker as Jedi Knight". The figure originally shipped with the tan tunic and was quickly corrected to black.
Most toy manufacturers feel that characters which are not expected to sell in large quanities often merit the "Limited Edition" label and are frequently found in the company's collector edition series.
If you need an example of this form of marketing, just take a long hard look at Hasbro's recent "G.I. Joe Classic Collection". Could someone please tell me just which one of these figures isn't a limited edition?! ...SHEESH!!!...
Most prototypes never leave the buildings of the manufacturer, but some do slip out to be sold on the secondary market. Sometimes they obtained by action figure magazines to be given away in a contest.
Most people don't explore this avenue of collecting due to the simple fact that nine out of ten of these "rarities" are fakes produced by talented con-artists. If you are interested pursuing these items, I strongly suggest you check the background of the individual trying to sell you a prototype figure and/or call the manufacturer to see if any were released.
An excellent example is the ever elusive "Malebogia" of the Spawn series from McFarlane Toys. There are a number of reasons this is done and it depends on what marketing strategy the toy company holds belief in.
Some of the more popular corporate rationalizations are:
Thus creating more demand than supply, and in turn the collectors will either buy other figures in the line, and/or force the retailer to purchase additional cases of the product from the manufacturer.