I am looking for an inexpensive sales tax API for shopsite pro. I need to collect tax in only one state and do not want a complicated program to do it.
ShopSite Pro already has this feature. In your control panel, go to: Commerce>Tax
For the radio button option entitled "Please choose a tax system:", choose "Use ZIP Code to determine sales tax".
Now press the configure button to choose what zip codes to assign what tax. The zip codes for the USA states have already been filled in for you but are editable.