I would like to associate an email address to our Non-Profit Tax Exempt entity - that would allow our entity to make on-line purchases without being charged tax. Is this posible?
If your organization is a legitimate registered non-profit group, giving you tax exempt status is up the seller. Normally the seller would ask for proof of tax exempt status for their sales records and invoice you accordingly. This would have nothing to do with your PayPal Account or associated email address.
