$ in excel formulas is used, I believe, to fix the source row or column number, e.g if you wanted a table to depend on the information in column C and row 13 you might do something like = $C12 - B$13, and dragging the formula around wouldn't lose this information.
To stop automatic evaluation is possible, but may depend on the version of excel you are using. The one I have is 2007, in which case you can go to Formulas >> Calculation Options >> Manual, and nothing will ever evaluate until you tell it to (by "calculate now" nearby).