Counterfeit.
Certainly the ones in booklets.
If you see them as commemorative sheets (usually only available at the PO for a short time) they are likely real.
There are discounted US stamps available on eBay that are the real thing.
Most are sold by stamp dealers whose listings are mostly stamps for collectors.
Dealers buy estates to get their (our) stock, and every philatelic estate includes pounds of mint never used stamps, valid for postage, purchased on subscription from the PO . We just hope the widow never added up how much the late collector was spending on them. She has enough grief to deal with.
Stamps are a hobby, not an investment.
If the dealer is selling stamps with a face value as well as the Forever stamps, all are probably the real thing.
The face value of this stamp is three cents.
If you are concerned, go for packets of counted, mint stamps (never hinged so no one ever licked them) and look for the best deal.
The USA has not demonetized any stamps since the Civil War, so you could use a mint Jenny Invert if you wanted too.
