I do agree to some of the comments and posts on this thread, the best way to invest your 0.1BTC is either through trading altcoins but it does take some time so you really need to have lots of patience for you to earn a certain amount. Then the other way to invest is through gambling; though it is the easiest way to increase your profit, it is also the riskiest way and so it might be the easiest way to lose your money too.
To invest in trade of altcoins you don't need only patience, but luck and some skills also to know which altcoin to choose, the one is more profitable and the one won't die very fast... Most of the altcoins are worthless coins that can lose price any moment, the pumps are fake and their real price is 0 or 1 satoshi... It's complicated.
Finally someone who is saying the truth, altcoin trading is a very hard way to generate profits, even when trader is having required skills and knowledge.
It is a very risky activity, because even these coins with great potential are in the pump&dump game, they are sometimes used as a tool for big players to get great returns with just pumping the particular alts with the bitcoins they own.
I still think that actually, forex trading is easier than altcoin trading, but everybody makes his own choices.