Questions about Futures contracts.

I have been investing in stocks, etf’s and mutual funds for quite awhile now. I am looking into experimenting with purchasing futures contracts. It seems that such are far more complicated assets. This is my main question is, if I purchase a 100 dollar contract is the maximum loss I can take on such $ 100, similar to a stock; or can you occur loses higher than the amount you initially out in out in, such as what can happen in short selling?