purchasePrice example

$products = [
            (new ProductBuilder($this->ids, 'product-1'))
                ->name('Silk')
                ->category('navi')
                ->customField('testField', 'Silk')
                ->visibility(TestDefaults::SALES_CHANNEL)
                ->tax('t1')
                ->manufacturer('m1')
                ->price(50, 50, 'default', 150, 150)
                ->releaseDate('2019-01-01 10:11:00')
                ->purchasePrice(0)
                ->stock(2)
                ->createdAt('2019-01-01 10:11:00')
                ->category('c1')
                ->category('c2')
                ->property('red', 'color')
                ->property('xl', 'size')
                ->customField('test_int', 19999)
                ->customField('test_date', (new \DateTime())->format('Y-m-d H:i:s'))
                ->customField('testFloatingField', 1.5)
                ->customField('test_bool', true)
                ->build(),
            (