Pennsylvania Statutes Title 72 P.S. Taxation and Fiscal Affairs § 3407-205. Sales presumed to be at retail

Every sale of tangible personal property shall be presumed to be at retail and to be taxable.  The seller may require any purchaser claiming that a sale is not taxable to give him a written statement signed by the purchaser and giving his address, certifying that the tangible personal property, the subject of the sale, is purchased for a purpose not included in the definition of “sale at retail.”  Such a certificate shall, in the absence of actual fraud on the part of the seller, justify him in failing to collect the tax.  If he fails to collect a tax on any sale where he does not obtain such a written statement from the purchaser, the seller shall be liable for the tax, as hereinafter provided, unless he shall sustain the burden of proving that the sale was not at retail.