SeeJ,
оно ?
<!doctype html>
<html lang="en">
<head>
<meta charset="UTF-8">
<style>
span {
border: 1px solid;
}
</style>
<title>Document</title>
<script src="//code.jquery.com/jquery-1.11.3.min.js"></script>
</head>
<body>
<table class="table-product-discounts">
<thead>
<tr>
<th>Кол-во</th>
<th>Скидка</th>
</tr>
</thead>
<tbody>
<tr>
<td>99</td>
<td>1%</td>
<td>лоремипсум</td>
</tr>
<tr>
<td>200</td>
<td>7%</td>
<td>лоремипсум</td>
</tr>
</tbody>
</table>
Quantity: <span id="quantity">99</span>
Result: <span id="result"> </span>
<script>
var quantity = +$('#quantity').html();
var result = $('#result');
$('td').each(function (inx, td){
var tdValue = +td.innerHTML;
if(tdValue >= quantity){
$(result).html(this.nextElementSibling.innerHTML);
}
return false;
});
</script>
</body>
</html>