Formula problem: percentage of dollar value - another dollar value *SOLVED*

Hello, I have a formula I am having trouble with. I am looking to take a dollar amount from a cell say A1 and subtract %2.9 from it and then subtract $0.30. I have a formula that works (=A1*0.029+0.3) but if there is no value in A1 it displays "%0.30".

any help would be greatly appreciated.
Thank you,
Jonathan