[рони]

nohc,
так на всякий случай ... кофициенты кроме pa и саму формулу sum уточните сами. ;жмите Показать исходный код

$(function () {
    var $spinner1 = $(".spinner-1"),
        $spinner2 = $(".spinner-2"),
        $spinner3 = $(".spinner-3");
    $spinner1.each(function (indx, element) {
        var el1 = $(element);
        var parent = el1.parents(".tab-pane");
        var old = 1,
            childs = 0,
            days = 12;
        var price = $("span[id^=price]", parent);
        var pa = +$('[name="pa"]', parent).val();
        var sum = function () {
            price.html((old * pa + childs * pa) * days)
        };
        sum()
        el1.tb3spinner({
            "value": 1,
            min: 1,
            max: 6,
            attrs: {
                "name": "old"
            },
            changed: function () {
                old = +$("input", el1).val();
                sum()
            }
        });
       var el2 = $spinner2.eq(indx);
        el2.tb3spinner({
            "value": 0,
            min: 0,
            max: 6,
            attrs: {
                "name": "childs"
            },
            changed: function () {
                childs = +$("input", el2).val();
                sum()
            }
        });
       var el3 = $spinner3.eq(indx);
        el3.tb3spinner({
            "value": 12,
            min: 12,
            max: 60,
            attrs: {
                "name": "days"
            },
            changed: function () {
                days = +$("input", el3).val();
                sum()
            }
        })
    })
});