I am new to Zen Cart and have installed the latest version (1.3.8a) on my server. So far, I have been able to figure most things out myself, but I have one issue with sales tax I am hoping someone can help me with.

What I want to do is essentially flag a certain attribute of a product such that when it is selected, sales tax will be added to the entire sale.

As a bit of background, I am putting together a photography store to sell individual images to clients and potential other customers. The plan is to make a separate product for each image and allow visitors to select the options they want for the photos (download full-resolution copy, purchase a print, and/or order image editing services).

Now, if the customer purchases just the digital download (and optionally image editing), there is no sales tax required by California state law. However, if a print of the photo is added to the order, it is required that sales tax be added to the entire order.

So, essentially, I want to make it such that if someone selects an attribute value of a print, sales tax will be added to the entire order.

I have explored other solutions including making separate items for downloadable images vs print images and including sales tax in the price for the print items. However, what it comes down to is that for each of these options I still have the issue that, by state law, I must add sales tax even to the downloadable items if anything physical is purchased, but I don't need sales tax for the downloadable items if nothing physical is purchased.

Thank you in advance for any help you can give me!