If you've never seen a block of adverts on a web page that included an "ads by Google" link at the bottom, you're one of a tiny minority. The web is largely funded by advertising nowadays, and Google is the leading company when it comes to helping web site owners profit from their sites.
In theory, advertising your own site in order to sell goods and services is simple. Just sign up with Google's Adwords system and create an account. Then create some ads, which can be done within your browser, and tell Google how much you're willing to spend each month to generate hits to your site.
Your ads will automatically be displayed on millions of relevant sites whose owners have signed up for the scheme, and all it costs you is a few cents each time someone clicks your ad.
However, if you ever thought that getting rich via online advertising was easy, you need to think again. Google makes it very easy for you to sign up to Adwords in order to start having your ads displayed, but fails to explain just how much time and effort you'll need to put into your online business in order to ensure that you're getting value for money. Despite what Google might claim, you can't just sign up for Adwords and then sit back while the money comes in. You need to be constantly experimenting with different ads, and examining the figures to see what works best.
If you're thinking of investing money with Google in order to sell things on your own site, you could do much worse than to start by reading the excellent article at http://www.huffingtonpost.com/jon-rognerud/5-ways-new-google-adverti_b_5... for a start. It explains the 5 most common mistakes that newcomers to online advertising make, and explains how not to make them yourself. While it may not make you a millionaire, it should at least help you avoid some of the most common pitfalls.