With Reference to this: https://developer.apple.com/app-store/review/guidelines/#mul...
3.1.3(b) Multiplatform Services: Apps that operate across multiple platforms may allow users to access content, subscriptions, or features they have acquired in your app on other platforms or your web site, including consumable items in multiplatform games, provided those items are also available as in-app purchases within the app.
Can i offer a differential pricing choice within my app. In other words if user buys on my 'website' the price is $100 and if user decides to make an in-app purchase, the price is, say, $130 (100 + 30% Apple Tax)?