Решил сам.
$(".mater").click(function () {
        if ($(".mater_checkbox:checked").length > 0) {
            mater_price = $(this)
                .children("td")
                .children("label")
                .children("input")
                .val();
            console.log(mater_price);
        } else {
            mater_price = 0;
            console.log(mater_price);
        }
    });