This idiom or expression has to do with:

Revealing a secret.
Giving away a surprise.

A. The birthday party was supposed to be a surprise. Who spilled the beans?
B. Your wife, boss! With all due respect, boss, you know how women are!
A. Yes I do, and here’s another surprise: You’re fired for spilling the beans about her!

This idiom or expression means:

Not worth much.
Of little or no value.

Q. How much is it? Is it valuable?
A. No, it doesn’t amount to a hill of beans!!

Also:
It isn’t worth sh-t. (Not very polite.)
It isn’t worth a rat’s ass. (Not very polite.)