Face value is $5. Collector value in Fine condition would be about $10 according to my not-too-far-out-of-date Blackbook.
It's still legal tender at face value, so yes.
Despite their age, $20 bills from the 1950 series rarely sell for more than a dollar or two above face value.
If worn, face value only. If it has only slight wear, it might retail for $7-8.
Face value only.
Despite its age your bill is only worth face value if it's in circulated condition. If it's nearly new in appearance it could retail for up to $70.
The face value of ANY bill or coin is simply another word for its denomination. Thus any $1 bill has a face value of a dollar, a $100 bill has a face value of one hundred dollars, and so on.The collector value of a bill or coin can be very different, depending on a number of factors. For more information about a 1923 $1 bill please see the question "What is the value of a 1923 US 1 dollar bill?"
20.00 dollar bill 2 face
Right now those are only worth face value. They just aren't rare.
Face value to $70 depending on condition
This is not a rare series date. In circulated condition it's only worth face value to maybe $7 or $8 if it has almost no visible wear.
Since this bill is not rare and is circulated it is worth face value.
$100 $100