Google AdWords lets you bid on keywords (rather than ranking for them, as with SEO) to appear on the Search Engine Results Page. You create ads and set targeting, and then you're entered into an auction with other advertisers who are also trying to show their ads.

I've been running AdWords for more than a decade, and I'll say - it's not for everyone. I have clients that are getting $1MM+ in revenue from their small AdWords program, and I've managed other clients where it would probably be a better business decision to stop marketing until they fix their funnels and landing pages.

If you're set up to grow your business online and you've got a good site or process to accomplish that, then using Google AdWords can be a very profitable way to get targeted visitors who are ready to buy from you.