Briefly, it works like this: A VAT is a tx that is applied at each stage of the manufacturing and sales process. For example, when an item is sold to a store, the buyer is assessed a VAT, then when a customer buys the item, he is assessed another VAT. This is common in Europe and other countries. A VAT often replaces part or all of an income tax. A sales tax is assessed only to the final buyer, not at the intermediate steps. It would s used in the U.S.

"Value Added Tax" (VAT) is a sales tax applied in the UK. Purchasers pay an extra % of the price to the seller on many goods and services. The money ends up in the coffers of the tax authorities. I have also seen EU legislation use the same term and abbreviation for sales taxes across the EU. I have not seen the expression "added sales tax" and so I don't know which country/countries it is used in. I would guess it's equivalent to VAT.

In Europe it is more frequent the use of the VAT; for example in Italy we call that IVA (Imposta sul Valore Aggiunto) and is a tax about all production in the State's territory. Every exchange between customers and sellers is subject to VAT. In Italy the IVA is at 22%. A sales tax is a tax paid to a governing body for the sales of certain goods and services, and it isn't used in Europe!

example: If I buy a TV for 1000$ the state tax could be 5% so it would cost 1050$. If I bought it in a city the city tax may be another5% so then the total cost would be 1100$