$("#slider").slider({
    ...
    slide: function(event, ui) {
        var delay = function() {
            var handleIndex = $(ui.handle).data('index.uiSliderHandle');
            var label = handleIndex == 0 ? '#min' : '#max';
            $(label).html('$' + ui.value).position({
                my: 'center top',
                at: 'center bottom',
                of: ui.handle,
                offset: "0, 10"
            });
        };

        // wait for the ui.handle to set its position
        setTimeout(delay, 5);
    }
});