I used to play penny stocks for fun and it was a blast to be doing $3000 trades and be responsible for 30% of the volume for the day. You can learn a lot about how markets work if you adopt a penny stock, particularly the kind that trades in a wide range where you can buy in at 0.03 and figure "I'll sell when it hits 0.12" and sooner or later it does... then falls back down to 0.02.