You got both sales tax and VAT wrong.Sales tax is not the same as VAT.
VAT is the same for for the entire nation so And VAT is included in the price.
VAT=tax added upon the selling price.
100$+25% VAT= 125$
sales tax= percentage of the sails price
100%+25% TAX= 75$ after tax
if you sell an app for 10$ and the VAT is 25%, you would just sell it for 12.5$
This means if you sell your app for 12.5$ epic would take 1.25$, the customer would pay you 2.5$ in VAT that you collect on the states behaf.
And iAP mechanism isn’t complicated to implement in your app, most of the time it’s quite literally a copy paste of code that is connected to your account. No development needed
Sales tax is a percentage on top of the price, not a percentage of the final price. $100 product, 8% sales tax, price is $108.
VAT is a tax on the value added, so price minus cost of materials (which have already been taxed) is the base for the tax, and then you multiply it by the percentage. So, for a $100 product, you subtract cost of materials (say $80), leaving $20. Then you would apply the 25% to that $20. Final cost is $105.