You typed "simple affiliate tracking software" into a search box because someone told you to start an affiliate program, and you want the least complicated way to do it. The first question is fair: is this a real thing to buy, or a phrase invented to sell you something?
It is real. It is a category, not a single app. It covers the hosted tools that let a small business recruit affiliates, track the sales they refer, and pay commissions, without an enterprise contract or a developer on staff. The names you will meet first are Rewardful, Refersion and Tapfiliate, and each is genuinely quick to stand up.
One thing to clear up early: this is affiliate program tracking, the software you run to manage your own partners. It is not the ad-click attribution that media buyers mean by "tracking" (RedTrack, Voluum and the like). Different job, different tools.
The regret, when there is one, rarely comes from the software. It comes from two places: paying a monthly fee before you have any affiliates, and picking a pricing model that gets expensive as the program grows. This review is about avoiding both.
If you want our pick up front: we'd start with unique coupon codes until five or more partners are selling, then move to the tool whose meter suits the business. That means Rewardful for SaaS billed through Stripe and Tapfiliate for a store with many small orders.