How do I advertise on CPA networks?

You have a few different ways to distribute your desktop product and using "big players" won't ensure you any quality.

1. You can always contact software distribution companies as tuguu, whitesmoke, bundlore and tens others to bundle your product inside their installers. The payout will change depand on your monetization category; the more your cross other client's the more expansive will be your monetization. Distribution country along with the compliance required is a ls a key factor for the pricing. You can get singular install for US market on 'freemium' category for around $0.2 per install.

2. If you have .exe installer and you don't bundle any other partner inside your installer >> your success rate should be 100% for any install you can contact CPA networks/ad-Networks as Yeahmobi, PLY and others and offer them around $1.2 CPI.

You can easily start working with any network with $5000 prepayment with other you can manage to work with $2000 prepayment or even NET30 if you tongue is sharp enough.

If you are monetizing sales or so, all the numbers above are incorrect

Best of luck with your product.