IAP revenue in free-to-play games comes from a small share of players, which makes payer conversion and spending depth the two levers to understand. Consumables (currency, boosters) and durables (characters, ad removal) behave differently, as do one-off purchases and recurring passes.
Timing matters as much as price. Offers presented before the player has built attachment tend to underperform however they are priced. Store platform fees and, increasingly, web shops change the net revenue per purchase.