Correct me if I am wrong but when it comes to numbers in Excel they are just that numbers. Excel allows you to "Format" the number to make it look a certain way but it is still a number. A perfect example is when a cell is formatted as date. If you put in the date 12/12/2015 it will actually be the NUMBER 42350. The same goes for currency if you put in the value $20.00 the cell is still holding the value 20 and then displaying it as $20.00.

With that out of the way I believe you may need to concatenate on a $ to make it a string. Otherwise where you put the value out to on the worksheet you can just ensure the format is in currency and it will show the dollar sign.

Again correct me if I am wrong.

Thanks