It will teach you how to use and operate any part of salesforce and is completely free. Lots of companies don't understand how to operate their own salesforce so this could get you a high paying job free.
Edit: People keep asking what saleforce is. salesforce is a way for a company to track everything that is done at a company. For example Amazon when you create a account you create a profile that they put into salesforce that keep track of who you are. this information then can be used to sell to you, creating a custom experience. Another use could be a bank that has many customers and want to know which customers are the most loyal, have the most referrals and other such factors.