AccountingCoach.com provides FREE online educational material to help you learn the accounting concepts practiced in the United States. The site provides hundreds of pages of explanations, drills, exams, crossword puzzles, and a glossary of over 1,000 terms.  
 
The World's Largest Free Online Accounting Course
Accounting is actually quite useful
SpearmintFur: If you wanna get into investing, it explains A LOT without the hype of those "get rich quick" books.  
 
I recommend learning accounting.