The following are the best way to earn money online through your PC or smartphone,

1. Paid surveys

You can earn $50 to $100 per month in cash and products by taking online surveys. Find survey sites by searching for “paid survey sites” online.Register with an email address, and check your email often so you can respond quickly to survey offers.
Most surveys pay up to $2, and the surveys generally take up to 40 minutes to complete.

2. Test website

Remote usability testing means getting paid to navigate a website for the first time and giving feedback to the website owner. Most tests take 15 minutes, and you can get paid up to $10 for each test. A test involves performing a scenario on the client’s website and recording yourself doing it. Sites that pay you to test websites include

User Testing ,
WhatUsersDo,

UserLytics,
UserFeel,

YouEye.

3. Online tutor students

Many families prefer the flexibility of using an online tutor. Depending on your background, you could be simply helping a child with homework or providing college-level support. You need to have your own computer and high speed internet. Experience required differs among companies. Some require strong experience, a specific educational background and college degree.
You can make anywhere from $9 to $30 per hour based on your educational background and the subject you teach.
Sites that hire elementary-level tutors include:

Tutor.com ,
HomeworkHelp.com ,

Aim4a and Brainfuse .
Kaplan hires SAT and ACT tutors.