Please post a new question with more detail. In particular, you'll need to supply the bill's series date, seal color/note type (ie. united states note). If it's older than series 1928, include a description of the images on the bill. You might need to find out who signed the bill. You don't need to copy the serial number, however.
I have a 1977 $100 bill and want to know the current value of it
Please don't assume that because a bill is old it has to be a silver certificate. As the banner across the top and green seal indicate, your bill is a Federal Reserve Note. See the question "What is the value of a 1934 US 100 dollar bill?" for more information.
US 1974 $100 bills were only issued in one series so there were none printed with a letter after the date. Perhaps you're looking at the Federal Reserve District letter or a plate-position indicator. There's more information at the question "What is the value of a 1974 US 100 dollar bill?"
It's still worth $100.
Please don't assume that every old bill is a silver certificate. As indicated by both its green seal and the banner over Franklin's portrait your bill is a Federal Reserve Note, not a silver certificate. The last $100 silver certificates were dated 1891. See the question "What is the value of a 1934 US 100 dollar bill?" for more information.
about 65-70 dollars
Please don't assume that every old bill is a silver certificate. As the bill's green seal and banner across its front indicate, it's a Federal Reserve Note. There's more information at the question "What is the value of a 1934 US 500 dollar bill?".
The U.S. did not print any $100 bills with that date.
At least $100 US dollars (isn't it obvious?)
100 Czech koruna is equivalent to 5.33951 US$
No. Cash does not expire. Though the value of what a 100 $ bill can buy can change over time, the bill as such will remain a $100 bill forever
Please don't assume that every old bill is a silver certificate. The last $100 silver certificates were printed back in 1891. The red seal and banner reading "UNITED STATES NOTE" at the top of your bill indicate it's a US Note rather than a silver certificate. Please see the question "What is the value of a 1966 US 100 dollar bill?" for more information.