"Rare" 1c George Washington & Benjamin Franklin Stamps on Postcards

We get a lot of folks that tell us they have a collection of postcards with "Rare Stamps".  Usually they're referring to stamps like these: 

    

These are usually common Washington–Franklin Issues, issued from 1908–1922, Benjamin Franklin 1902 series issued from 1902-1917 and US Regular Issues issued from 1922-1931.

Most of these stamps were printed in quantities that reach into the billions, so they are definitely not rare by any account.  Just because something is 100+ years old, doesn't make it valuable.  Scarcity and collector demand make things valuable.  

"But I just Googled these stamps and they're selling for $50,000!" you say?

Perhaps you see something like this:

First, it's doubtful that any of those stamps have actually sold for that much.  You need to look at SOLD prices [ebay.com], and even then many of those sales for common stamps may not actually be real.  There may be a few of these there that sell for more than $1, but for used 1c stamps on postcards, usually it's because of the cancel or postmark, or other factors that make it more desirable.  There may be a minutiae variation that make a stamp rare. Looking at auction results from well-known stamp auctions is usually a better indication of market value, but there are plenty of high-end collectibles that sell on Ebay as well. 

A better gauge of retail stamp prices is usually Mystic Stamp Co.  Here's a typical used #300 1c Franklin for 15c, same for the used #424 1c George Washington.  Collectors aren't usually interested in used common stamps, although on a postcard you might find more interest along with an unusual cancel...

Second you need to look at condition.  If it's a used stamp on a postcard, it's not mint.  

Third, look at WHO is selling the stamp.  Most of the ads you'll see on Google are from Ebay or Etsy sellers that have few or zero sales/feedback.  Is there any supporting documentation or images?  Usually for an expensive stamp you should expect to see very high quality images as well the Scott # and supporting details. 

So why are these sellers advertising stamps that are not worth anywhere near that much? 

It's unclear, what the benefit is for sellers who only have one listing for a massively overpriced item.  Ebay, Etsy and other marketplaces allow anyone to list pretty much anything for any amount.  These items are then automatically searchable and advertised on major search engines like Google and other ad networks. 

Maybe it's just wishful thinking, or unscrupulous sellers trying to pass off common stamps as rare, or hoping to selling something for a huge profit to some unsuspecting or uninformed buyer.

While the vast majority of these stamps have a "Book Value" of 25c or less (and nobody really pays book value for most stamps, especially the lower-end ones), there are some rare stamps to be found.

The Scott #594 & #596 for example can sell for thousands of dollars, but out of the billions of similar stamps there are only a handful of these known to exist.  These were only from 1923 and have very specific characteristics that distinguish them from the usual common varieties. 

So is that "rare" 1c stamp you have on grandma's postcard worth anything?  Maybe, but 99.9999% of the time it's your typical garden variety stamp.