this line is likely the same as setting the "Search for" field of InDesigns Grep search to "\$(\d*.\d*)".
You tell InDesign to search for a Dollar sign, followed by "zero or more" digits, one "any character" and then again by "zero or more" digits.
(this line does not automatically start your search. It only prepares the search enging for finding this pattern)
With this line you will find: