Andree007,
<!DOCTYPE html>
<html>
<head>
<title>Untitled</title>
<meta charset="utf-8">
<style type="text/css">
</style>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.4/jquery.min.js"></script>
<script>
$(function() {
$("input").on("input click", function() {
var items = document.querySelectorAll('[type="number"][data-factor]');
var z = [].reduce.call(items, function(sum, el) {
var num = +el.value || 0,
factor = +el.dataset.factor || 0;
return sum + num * factor
}, 0);
items = document.querySelectorAll('[type="checkbox"]');
z = [].reduce.call(items, function(sum, el) {
var up = +el.dataset.up || 0,
factor = +el.dataset.factor || 0;
return !el.checked ? sum : up ? sum + up : sum + z * factor
}, z);
$("#rezz").html(z.toFixed(2) + " Рублей")
})
});
</script>
</head>
<body>
<form method=post id="myform">
<table border="2" cellpadding="0" cellspacing="0" height="200" width="650" id="" >
<tbody>
<tr>
<td valign="top" width="180">Сварка </td>
<td valign="top" width="80">7,5 р / см</td>
<td valign="top" width=""><input data-factor="7.5" type="number"></td>
</tr>
<tr>
<td valign="top" width="180">Рез, зачистка реза, сборка</td>
<td valign="top" width="80">32 р / шт</td>
<td valign="top" width="80"><input data-factor="32" type="number"></td>
</tr>
<tr>
<td valign="top" width="180">Зачистка шва</td>
<td valign="top" width="80">2 р / см</td>
<td valign="top" width="80"><input data-factor="2" type="number"></td>
</tr>
<tr>
<td valign="top" width="180">Покраска, обезжиривание, грунт (лист)</td>
<td valign="top" width="80">230 р / м.кв</td>
<td valign="top" width="80"><input data-factor="230" type="number"></td>
</tr>
<tr>
<td valign="top" width="180">Покраска, обезжиривание, грунт (профиль)</td>
<td valign="top" width="80">30 р /м.п</td>
<td valign="top" width="80"><input data-factor="30" type="number"></td>
</tr>
<tr>
<td valign="top" width="180">Шпаклевка шва</td>
<td valign="top" width="80">15 р / шт</td>
<td valign="top" width="80"><input data-factor="15" type="number"></td>
</tr>
<tr>
<td valign="top" width="180">Шлифовка шва </td>
<td valign="top" width="80">36 р / шт</td>
<td valign="top" width="80"><input data-factor="36" type="number"></td>
</tr>
<tr>
<td valign="top" width="180">Монтаж на объекте</td>
<td valign="top" width="80">20%</td>
<td valign="top" width="80"><input type="checkbox" data-factor=".2"></td>
</tr>
<tr>
<td valign="top" width="180">Дизайн</td>
<td valign="top" width="80">30%</td>
<td valign="top" width="80"><input type="checkbox" data-factor=".3"></td>
</tr>
<tr>
<td valign="top" width="180">Выезд замерщика</td>
<td valign="top" width="80">800р </td>
<td valign="top" width="80"><input type="checkbox" data-up="800"></td>
</tr>
<tr>
<td valign="top" width="280"><div id="rezz">итог</div></td>
<td valign="top" width="50"></td>
</tr>
</tbody>
</table>
</form>
</body>
</html>