How much does ItsDeductible cost?
TurboTax ItsDeductible is a free program available online or as a mobile app.
However, if you download the mobile app, you'll be prompted for credit card info when you first set up your iTunes account. This occurs regardless of which program, free or otherwise, you want to download through the iTunes Store.
Fortunately, there is a way to set up an iTunes account without providing payment. Follow these instructions at the Apple support site.