public function change_sorter_based_on_price_display() {
		if ( is_admin() ) {
			return;
		}

		$settings = INVP::settings();
		if ( ! isset( $settings['price_display'] ) ) {
			return;
		}

		if ( isset( $_GET['orderby'] ) && apply_filters( 'invp_prefix_meta_key', 'price' ) == $_GET['orderby'] ) {
			add_action( 'pre_get_posts', array( $this, 'change_price_field_when_sorting' ) );
		}

		switch ( $settings['price_display'] ) {

			case 'down_only':
				// add down payment to the sort drop down.
				add_filter( 'invp_sort_dropdown_options', array( $this, 'add_down_payment_to_sort_dropdown' ) );
				// and remove price.
				add_filter( 'invp_sort_dropdown_options', array( $this, 'remove_price_from_sort_dropdown' ) );
				break;

			case 'call_for_price':
				// no prices available, remove price from the drop down.
				add_filter( 'invp_sort_dropdown_options', array( $this, 'remove_price_from_sort_dropdown' ) );
				break;
		}
	}