Do organizations who endorse a senate bill always contribute money to
it, or is this not required/ common?

A bill can't receive money.  Perhaps you could explain your question in more detail.

For example, when there's a proposition for a new bill, organizations
often will support or fight the proposition. If they support it, they
contibute money towards the cause of the bill. I was wondering if
those who announce "support" of a particular bill are required to
contribute money towards pushing that to pass, or often contribute, or
rarely contribute (they just say they're in support of it).