1966 $100.00 dollar bill w/red seal..

Probably one hundred dollars. No one can tell you the value of a coin or a bill without seeing it. If it is uncirculated, i.e., if it was never used, it might be worth more than $100. Otherwise, it is unlikely to be worth more than its face value. The fact that it is a United States note doesn't mean much.

aint that the fact jack

is it less than much

and a hundred dollars goes a lot less far today than it did in 1966, so it isn't even worth now what it was then. spend it quick, in other words.