......brutal honesty time.
nano tanks are tough..... picos are even tougher. IMO someone brand new to the hobby should not attempt a pico, it's just going to be VERY frustrating, and probably cause you to leave the hobby.
I would start with something such as a 30g long, or a 40B would be perfect to get you started in this hobby. They're a bit more expensive.... however they're going to be a lot easier, and last you longer, and won't upset you every time you see a fish in the LFS and can't buy it....
if you are thinking pico due to money issues, then i would hold off, research, and save your money.