Whatever the first class postage rate is. Currently 49 cents.
Yes
This is a common stamp worth 4 cents in mint NH condition.
I don't see any writing on the flag. The lower right of the stamp has the year in small numbers, but there is nothing on the flag itself.
one dollar
No, only one Forever stamp has been issued. It has a value of 44 cents currently. There is a listing of USPS postage stamps that have been issued without values on their website.
39 cents
According to the USPS website, under "Buy Stamps", then "Rate Change", the brown background non-denominated US Flag stamp is $.41. The US flag is one of the most popular subjects for a Postage Stamp and can be found on dozens of them. The value of each will be dependent upon condition and rarity. You would have to identify the specific stamp to determine the value.
thirty-two cents according this this site http://www.akdart.com/postrate.html
The ivory colored American flag stamp was issued back on 4/12/2007 and face value is .41.
The stamp without any face value shown is worth 39 cents. It can be used for that amount of postage. Check the USPS web site for pictures and other things.
Flag Day is on Thursday, June 14th, 2012.
29 cents