The system varies based on countries:
In most countries you set the price in the Play Console which includes the tax. E.g. You set a price of $2 inc. tax 20%. User pays $2. This means the price with no tax is $1.67. Now Google takes its 30% and you're left with $1.17
In some other countries, E.g United States, you set the price with no tax and then the tax is added on automatically as it varies by state. E.g. You set a price with no tax of $2. Tax is 20% so user pays $2.40. Google takes its 30% and you get $1.40.
Please note: Values used for demonstration purposes
After these calculations are made, the money gets added on to your Google Play Console Account. On the 15th day of the month, if your earnings are over the payment threshold, the money will be transferred to your bank account. This usually takes a few days.
america adds VAT also depending on state regulations so it can vary nationally- don't take fixed price advice