Using the jigoshop_sale_price filter to give Paid Memberships Pro members a site-wide discount.

gistfile1.txt

function my_jigoshop_sale_price($price, $product)
{
	if(pmpro_hasMembershipLevel())
	{
		//no sale price yet?
		if(empty($price))
			$price = $product->get_price();
		
		$price = intval(($price * 0.90)*100)/100;
	}
	
	return $price;
}
add_filter("jigoshop_sale_price", "my_jigoshop_sale_price", 10, 2);