If you want to have your taxes included into the price of the product turn on the setting 'I will enter prices inclusive of tax.' With this setting turned on, the system will not add taxes on top of your selling total (i.e. if you set up a price for 1g of one of the products at $10.00, the total your customers will pay will be $10.00). Then we will deduct taxes from this total for reporting purposes.
This setting is only available for a single tax tier (can't be used with multiple tax tiers) and the setting 'Apply local tax to the business tax amount' must be turned off.