purchase tax 
noun
A tax added to the price of goods sold to consumers: car tax was an additional purchase tax that has since been abolished...
- ‘The Irish government has doggedly held on to a car purchase tax, even though excise duty on cars was abolished as far back as 1992,’ he said.
- The purchase tax is tiered from 9 to 13 per cent.
- As for the touted benefits for the consumer and businesses, credit cards can truly be regarded as an additional purchase tax and, ipso facto, a huge drain on the economy.