why use json stringify and parse code example

Example: get value from JSON.stringify

var obj = '[{"availability_id":"109465","date":"2017-02-21","price":"430000"},{"availability_id":"109466","date":"2017-02-22","price":"430000"},{"availability_id":"109467","date":"2017-02-23","price":"430000"}]';
var stringify = JSON.parse(obj);
for (var i = 0; i < stringify.length; i++) {
    console.log(stringify[i]['price']);
}