Log into your website manager

Click on the Catalog Setup link.

Set the Tax/Costs field to Yes.

Click on the update variables button at the bottom.

Add or Edit a Product and enter the tax percent for the product
( if you leave it set to zero no sales tax will be charged for the product).

Log into your Mals-e account ( http://www.mals-e.com ).

Click on Cart Setup.

Click on Sales Tax.

Look for TAX BASIS - click on the radio button next to -
"Tax will be calculated using a rate set in your Buy Now links in the field named tax."

Use option from 1-5.

Look for PRICES - click on the radio button next to - "sales tax should be added to my prices".

Click in the Submit changes button.

Test you cart to make sure everything is working.