The minimum they are worth is their face value. They are still valid postage.
A quick look on eBay found one could purchase a full sheet (32) for $4.99, plus $4 shipping.
http://cgi.eBay.com/U-S-Postage-Full-Sheet-6-cent-Stamps-Dwight-Eisenhower_W0QQitemZ260182274428QQihZ016QQcategoryZ265QQrdZ1QQssPageNameZWD1VQQ_trksidZp1638.m118.l1247QQcmdZViewItem
Sorry, I am unable to find a 2 cent Eisenhower stamp. Please consult a catalog and try to identify which stamp it is. Your library will have Scott Catalogs which can help you.
priceless
8 cents.
every stamp is worth it
The value of a six pence stamp will depend on the year of the stamp, and the condition of the stamp.
In perfect condition it is worth 25 cents.
It is worth 2 cents.
Its worth about $2.
It is not worth anything
That would be Scott number US 2496. A full sheet of these stamps has a catalog value of $44.10.
It will depend on the specific stamp issue. It could be minimal, worth 15 cents postage for each stamp. They may be 50 or 100 stamps to a sheet. There are some very early 15 cent stamps that could be worth many dollars each. Consult a good stamp catalog to identify the stamp and its value.
That would be Scott number US 1124. A full sheet of these stamps has a catalog value of $11.00.