I was researching dynamic IAP options and exploring how other apps handle this when I stumbled upon an interesting UX in TikTok. TikTok offers a feature that allows users to promote their own or another user’s post. The UI enables users to slide the promotion price anywhere from $6 to $1400 a day. Once you set the desired budget, the price is specified, for example, as $15.71. At this point, I thought TikTok might be using some sort of in-app currency since IAPs typically don’t support such precise pricing. However, when I pressed the Pay button, I noticed that TikTok somehow presents this exact price as an IAP (the price on first two screens is in SGD while it's presented in USD on the 3rd screenshot). Question: How are they doing this? How does one get access to offer IAPs with dynamic pricing?