I'm not sure how your desired result is supposed to look like, but either way you can just iterate over your object:

// let obj = JSON.stringify($('form').serializeObject())
let obj = {"costPerDay":"20","numberOfDays":"20","designCost":"40","cmsIntegration":"64","seoContentStrategy":"75"};

$("#result").empty().append("<ul></ul>");
for (const entry in obj){
    $("#result > ul").append(`<li>${entry}: ${obj[entry]}</li>`);
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div id="result"></div>

Or if you prefer a single-liner:

$("#result").empty().append(
    "<ul>" + Object.entries(obj).map(e => `<li>${e[0]}: ${e[1]}`).join("") + "</ul>"
);

Working demo:

http://jsfiddle.net/7a5xjwbh/

I guess the code you made does not work, maybe this will help you better figure out what i am aiming for, attached is the full code that I wanted the output as "Unordered List" and the source in CodePen http://jsfiddle.net/JOEHOELLER/217m94fk/2/ If you want to check out the working Range Slider. Thanks

function proRangeSlider(sliderid, outputid, colorclass) {
        var x = document.getElementById(sliderid).value;  
        document.getElementById(outputid).innerHTML = x;
        document.getElementById(sliderid).setAttribute('class', colorclass);
        
        updateTotal();
}

var total = 0;
function updateTotal() {
        var list= document.getElementsByClassName("range");
        [].forEach.call(list, function(el) {
            console.log(el.value);
            total += parseInt(el.value);
        }); 
        document.getElementById("n_total").innerHTML = total;
      
}
$.fn.serializeObject = function()
{
    var o = {};
    var a = this.serializeArray();
    $.each(a, function() {
        if (o[this.name] !== undefined) {
            if (!o[this.name].push) {
                o[this.name] = [o[this.name]];
            }
            o[this.name].push(this.value || '');
        } else {
            o[this.name] = this.value || '';
        }
    });
    return o;
};

$(function() {
    $('form').submit(function() {
        $('#result').text(JSON.stringify($('form').serializeObject()));
        return false;
    });
});