Change a cell formula base on Month

I need to create a cell in Excel that will work a formula during a certain month and will display a numeric value when it is not that particular month (it is for a daily expenditure value that automatically decrements daily for that particular month).

I have the formula to change the value of the cell - {=((30)-DAY(TODAY()))*100} and it works fine.  I want to write an IF formula that will only use that formula for the month of that budget tab.

Here is the last formula I have tried (without success) - =IF(MONTH(8), then_value,=((30)-DAY(TODAY()))*100, otherwise_value, "3000.00")

In summary, I want the budget tab for August to count down based on the day of the month, but I want every other tabs (the other 11 months) to display a straight numeric value (preferably "0.00" for January - July and "3000.00 for September - December)

I've exhausted everything I can think of to try.  If you can help me I would greatly appreciate it.

Thank you.

Ed