For most serious apps, monetization is essential for sustainable development.
Light ads generate negligible minuscule revenue. Aggressive ads is very detrimental to user experience.
In-app purchase (IAP) usually is the primary monetization means.
- Make the IAP process extremely easy. Many users buy to gain benefits they need, many are kind enough to buy to support app development. Most IAP customers have both intentions. If the FREE version has the most basic functions, users' kindness plays a very important role in deciding to purchase a Pro license. If the IAP process is very easy and convenient, these users will do it. If not, only some of them will be willing to invest in the effort to do the purchase. For example, if an IAP function stops working due to a technical glitch, few users would bother to report it to the developer.
- Make the upgrade option available even during a Pro version trial. A Free Pro version trial option is helpful. It is very important to allow users to upgrade conveniently during the trial. Do not make the IAP available only after the trial ends. Many kind users decide to make the IAP within hours after trying the Pro version. The IAP price usually is a very small amount compared with what they have already invested in things associated with the app.
- Make it crystal clear if a license is permanent, not a subscription, and can be used on multiple devices. Many users are not familiar with this common policy of digital goods.