Bogus

Bogus stamps are: They are totally made up to defraud collectors. Contrast that with forgeries being false reproductions of existing stamps. So, yes, a forgery of a bogus stamp is indeed possible.
 * productions of nonexistent countries or territories.
 * productions posing as an official issue of a country but never existed. These are illegal stamps.

They have been created since stamps began. Recently there have been many 21st Century issues pretending to be from various French Community African countries. In the 1990s following the breakup of the Soviet Union, many bogus overprints of various designs appeared on Russian definitives.

Be aware that some recent proven bogus issues have been listed by major catalogs. While the catalog editors have been notified, those listings won't be deleted until the next edition of the catalog.

 File:Somalia bogus.jpg|Bogus stamp for Somalia. File:PMR bogus.jpg|Bogus stamp for the Pridnestrovian Moldavian Republic. File:Karelia bogus.jpg|Bogus Russian Karelia surcharge. File:South Moluccas A.jpg|Bogus South Moluccas stamp. These were printed by a group not at all connected with the rebellion in that area. 

Now, nobody's going to stop you from buying these because you like them. But realize that instead of printing tons of junk mail flyers every week, the fakers/counterfeiters are just using better paper and perforation machines. So you are overpaying for these images by many, many times. Further, they are not paying royalties to your favorite star or celebrity, so what kind of fan does that make you?