Think the most valuable lesson I have ever learned, is that every penny will fry you.
When I started learning to trade I started in penny and sub penny land, and got ripped up.
Did some studying, got a job at a prop firm trading big boards, and then came back to pennies after a few years of experience.
If you don't know anyone, and you don't want to gamble, pennies are the worst if you break the most basic rules, and for me as a day trader on big boards as a career choice, and pennies as a hobby, that rule is to take profits quick, and take losses quicker lol.
Atleast from my experience that is what this beast known as the market has taught me ;)
Best of luck everyone!