No, there’s not a good way. Some taxes are hidden, some are itemized on receipts. Different taxes go to different authorities and are paid in different ways. You’ll need to be really thorough in your bookkeeping and list every line item of every bill and every receipt to track it, and even then you’ll miss some.
I’ll give you some examples:
VAT or sales taxes: different items may be taxed at different rates. Purchases in different areas may be taxed at different rates. Prices may be inclusive of the tax or exclusive (e.g.: in countries where VAT is charged, retail prices are almost always inclusive of VAT, although the total VAT charged should also appear somewhere on the receipt).
Tariffs and other indirect taxes: these are usually hidden within the price unless you are the one handling the import customs. Most people pay these taxes as part of the purchase price and will never see the actual tax component of the price.
Commodities and utilities taxes: you mentioned gas tax, it is usually included in the price of gas. It may or may not be explicitly itemized on the receipt (e.g.: in California there’s a high gas tax, but it is not actually shown on receipts – it’s just part of the gas price). Similarly, there are taxes tucked into your utilities bills, phone bills, internet bills, etc.
It is safe to assume that any time money exchanges hands, there’s a tax component. However it may be difficult to estimate how much exactly it is to the last cent, and who’s actually paying it. Consider payroll taxes – sure, you have a “social security” line item in your payslip, but your employer also pays a similar tax. At whose expense is that? You buy imported goods, importer paid tariffs (customs duty) and tacked them on top of their costs and profit margins as part of the retail price you saw – so who actually paid the tariff?
Also, consider that taxes are not directly tied to income. Income taxes, obviously, are. But consumption taxes (sales, customs/tariffs), value added (VAT), property taxes – they’re not. These are usually considered “regressive” taxes: the lower your net worth/income is, the higher percentage of it is the tax. This is opposed to “progressive” income taxes: the higher the income, the higher the percentage of it that goes to the tax. Even payroll taxes, even though technically income taxes, are regressive: there’s a cap on social security tax, unemployment tax, etc. The higher the income, the lower overall percentage of it goes to the tax.
