First Class postage was 32 cents beginning on January 1, 1995. The rate was increased from 29 cents on that date. It was in effect until the rate was increased to 33 cents on January 10, 1999.
{| |- | It will depend upon which of the two First Day Covers you have. There were two stamps issued in March of 1978. The value is $1 to $2, though the cachet (the picture on the envelope) can also affect value. |}
There isn't enough information to answer. You need to consult a postage stamp catalog that includes the First Day of Issue prices. Check your local library.
Unmarked means it is not on cover and not cancelled. Which means it can't be a First Day of Issue. A First Day of Issue cover could cost 2 or 3 dollars. The individual stamp can be purchased for less than a dollar.
1968
Issue price was $5.00 current value is $8.00
This stamp made in 1968 is worth 20 cents used and 40 cents unused.These stamps were not made in 1734.
Issue price was $5.00, current retail value is $10.00.
The cost of a First Class US postage stamp in 1968 was 5 cents. It was raised to 6 cents on January 8th. It stayed at 6 cents until 1971 when it went to 8 cents.
Cost of a postage stamp was dependant on the face value of the stamp. The most common rate stamp is for First Class Mail. In the United States 1968 that was 6 cents for the first ounce. For the first week of 1968 it was only 5 cents.
Scott #1354. This stamp was issued in 1968. It was part of a ten stamp set printed on single sheets. A mint copy can be purchased online for $1. A used copy is 65 cents.
In the US a first class stamp cost 5 cents in the US. A postcard cost 4 cents. It went to 6 cents in January of 1968.
The cost of a stamp changed in 1968. It started off the year at 5 cents. At the end of the first week of January it went up to 6 cents.
1968
The cost of a first class postage stamp in the 60's started at 4 cents. It went to 5 cents in January 1963 and then to six cents in January of 1968.