GU has a corporate Amazon account which allows tax-exempt purchases for business-related purchases.
To be added as a purchaser on the GU Amazon account, please send your request to email@example.com.
Once you have been added as a buyer, you can make tax-exempt business purchases by logging into Amazon with your work email and selecting the items you need. If the vendor is located in a state in which GU has a sales tax exemption, the taxes will be removed from your cart at check-out.
You can find more on tax-exempt purchases here.