1/3 I think.
How much is one tempo worth?
I'm no authority on the subject nor am I any good, but counting tempi in terms of material has never been helpful for me.

When both sides are racing to queen a pawn or mate each other's king, a tempo can be the difference between victory and defeat. In those cases, it's worth quite a bit.

i said that's what my grandpa say but hes senile and pisses his pants
Blame it on whoever 'designed' the urethra to be placed right in the middle of the prostate gland. Placing a sewage pipe right in the middle of a gradually expanding entertainment center is poor engineering, but I guess evolution didn't ask my opinion.

If one tempo is worth thirteen dollars, what is the value of a zugzwang?
Negative 1 game of chess.
The correct answer was 0.33 Pawn. That you can quantify it better if you know the exact position, and that it can be more than a Queen in such a case, are trivial remarks that of course apply to all material values. By definition such values are averages over all possible positions, the best you can say without having any knowledge other than the material present.
Note that the difference between white and black in the opening position is only half a tempo: white has to lose a full tempo to reverse the difference. The value of 0.33 then fits well with the observation that Pawn odds causes an average score of 68% (i.e. 18% above equal), while the white advantage is only about 53% (3% above equal), between equally strong opponents. (E.g. in self-play of computer programs.)
The correct answer was 0.33 Pawn. That you can quantify it better if you know the exact position, and that it can be more than a Queen in such a case, are trivial remarks that of course apply to all material values. By definition such values are averages over all possible positions, the best you can say without having any knowledge other than the material present.
Note that the difference between white and black in the opening position is only half a tempo: white has to lose a full tempo to reverse the difference. The value of 0.33 then fits well with the observation that Pawn odds causes an average score of 68% (i.e. 18% above equal), while the white advantage is only about 53% (3% above equal), between equally strong opponents. (E.g. in self-play of computer programs.)
well i totally agree with the first half, but i dont have any clue about the second half...

i said that's what my grandpa say but hes senile and pisses his pants
Two elderly gentlemen, old friends, are sitting on a park bench, talking.
"So, Abe, how are you feeling these days?"
"Well, I'll tell ya, Bernie. I feel just like a newborn babe."
"Really, Abe? Like a newborn babe you say?"
"Yeah, Bernie. I got no hair, I got no teeth ... and I think I just peed my pants."
How much is one tempo worth (with the pawn 1 knight and bishop 3 rook 5 queen 9 system)?