I bought SKTO back in March 2013, got it for under 1/2 of a penny and made a nice profit during its run up. They're all roller coaster rides and very speculative. There's a lot of manipulation on all the pot stocks, so be careful if you ever decide to give it a shot. I still hold quite a few 'free' shares, just in case it makes one of those mysterious runs like MDBX or MJNA
have to throw this in here, i saw a penny stock BITC jump up 2400% in one day...it claims its a bitcoin exchange company with a rinky-dinky website, but just a few weeks ago it was gold mining company and just got its ticker changed to BITC...pure speculation.