Ask HN: Referral fees and marketing a new product?

I'm a forties something software engineer with a heavy slant towards finance that has spent my life working for other people (still am). Lately I have been working on a personal finance application in my free time (think Quicken or Mint). I have used many of the offerings currently available and grown frustrated with them over the course of 20+ years using these different tools and never being able to change what I saw as shortcomings in the available tools.

This started out as just, "I'm tired of X, Y, and Z so I'm just going to build the damn thing I want." And even if I'm the only user ever; I will continue to build this for myself.

That said I think that maybe other people would be interested in the software, but I don't know really anything about marketing. I know some companies use referral fees, but I don't know much about them. Do you use flat fees or percentage of sale and what's the right pricing? If a customer was referred and later purchases an upgrade or adds a subscription service do you pay an additional "bonus" referral fee to the referrer? Who do I contact to let them know about my application to get them to plug/market it for me and how best do I go about this?

Any other pointers would be greatly appreciated.

At this time I'm not linking to my product as it is an installable desktop application (I know; old school nobody want that anymore...) and I haven't yet created a website on which to market it. I also don't want the focus here to be on my product specifically, but on how I would market it or other products in general.