The lowest value US stamp was the 1/2 cent. A couple different versions were issued.
$0.20
.75
Today (February 4, 2015) it is worth 80 cents US.
Worth 6 cents
8 cents.
The US issued a Chester W Nimitz stamp.
I have an old paper food stamp and i was wanting to know what it would be worth now. It's a 1999 $1.00 paper stamp. It's in great shape.
39 cents
Air mail stamps are good for ordinary postage- your stamp is still worth 7 cents if unused.
A US first class stamp dated 2002 is worth face value only, and it's still valid now.
50 cents if unused. Nothing if used.This must be the most common US airmail stamp.
That is Scott number US 2998 issued in 1995. A mint copy will cost you $2.60 and a used copy 30 cents.