[ksa]

'"{"1":{"id":1,"name":"Артикул 2","price":299,"num":1,"url":"http://site/","photo":""},"2":{"id":2,"name":"Артикул 2","price":220,"num":1,"url":"http://site/","photo":""},"3":{"id":3,"name":"Артикул 6","price":179,"num":1,"url":"http://site/","photo":""}}"'

Второй и предпоследний символ - лишние.

order.length === undefined;

У объекта нет такого свойства.

Мне необходимо сделать список всех 'name' и вывести сумму всех 'price'

var str='{"1":{"id":1,"name":"Артикул 2","price":299,"num":1,"url":"http://site/","photo":""},"2":{"id":2,"name":"Артикул 2","price":220,"num":1,"url":"http://site/","photo":""},"3":{"id":3,"name":"Артикул 6","price":179,"num":1,"url":"http://site/","photo":""}}'
var o = JSON.parse(str);
var sum=0;
for (var i in o) {
	alert(o[i].name);
	sum+=o[i].price;
};
alert('sum='+sum);