If the "financial software" is, say, an accounting program, and it costs you less than a typical monthly cell phone bill (such as Quicken), I'd expense it under legal/professional (bookkeeping) expense. For that matter, I'd expense the cost of the more expensive QuickBooks.
If it costs thousands or hundreds of dollars, as accounting software used to cost, and if you plan to use that software for multiple years, you're going to need to call it an asset and depreciate it. In that case I don't know what would be the asses category.