When defining the price of the item you can include the tax rate.
1. Go to Gateway of Tally > Inventory Info. > Stock Items > Create/Alter > F12: Configure .
2. Set Allow inclusive of tax for stock items to Yes .
3. Press Ctrl+A to go to the Stock Item Alteration screen.
4. Set Is inclusive of duties and taxes? to Yes .
5. Enter the Rate of Duty , as required.
6. Press Ctrl+A to save the ledger.