Yes one can make money buying and selling penny stocks.
However, though in theory you would double your 100 dollars on paper after buying and selling fees your profit would not actually be double.
Since .0001 is the lowest a stock trades at there is no where down from that price, unless the company goes under.
At .0001 you would be able to buy a million shares with a 100 bucks plus trade fee. Personally if I did something like that I would sit on it until it at least broke .0005, but even that what just be to build my capitol to reinvest.