Most commercially produced First Day Covers of standard commemoratives like this are typically worth a dollar or two. They can be purchased for on eBay or through dealers. Higher value stamps, or specific cachet makers are worth more. A specialized catalog will list the value of a cachet or un-cacheted cover.
The US Mint has not issued any half dollars depicting Lyndon Johnson.
Scott number 1503 has a catalog value of 40 cents in mint condition.
$317,200
About a $1.
about 2 dollars
It is called the First Day of Issue. Cancellations on that date have value. Cancellations before that date are really sought after!
Scott Number 1359. Catalog value is $2.95.
The first issue of Playboy magazine, published in 1953, featuring Marilyn Monroe on the cover, is considered a collector's item and can be worth thousands of dollars depending on its condition and rarity. It is advisable to consult with a specialist or appraiser to determine the exact value.
1796 is the first year of issue, post new question.
The first year issue for a Indian Head cent was 1859
Not sure what you may have, as the US did not issue a Christmas Stamp in the year 2000.
There wasn't any Lincoln First Day in 1952. The nearest to that was in 1954. The catalog value of a 1954 FDC is $1.50