Below is a table of the alphabet stamps and the associated rate changes since the first alphabet stamp was issued - note 1981, in particular - they raised the rates twice in one year! Yes, all of these are still valid as postage, at the rate shown below.
STAMP VALUE DATE of rate change
A 15 cents 5/29/78
B 18 cents 3/22/81
C 20 cents 11/1/81 (!)
D 22 cents 2/17/85
E 25 cents 4/3/88
F 29 cents 2/3/91
... F makeup rate 4 cents
G 32 cents 1/1/95
... G makeup rate 3 cents
H 33 cents 1/10/99
... H makeup rate 1 cent
(no I stamp) 34 cents 1/7/01
1|1|Thanks I have a G&H stamp, didn't know what it was worth.|seahawk|Seahawks57@aol.com|18:32:57|02/13/2011|
seahawk