If not mine BTC what other coin is it worth to mine nowadays?
mining does not always require a capital or huge capital before you get started because even if you do not have a cash in your pocket , you can still possibly mine a crypto due to the fact that there were now lots of mining sites that you can use nowadays and yes most of them are totally free and easy to use . however the profit that you might get is litteraly small if you are only using a third party service .
2018 is a more advance year when compared to the past year and many people are now also doing mining , so there is a slight difficulty which can affect your gains . although the profit will still depend on the device that you are using .
I suggest you not to invest in mining now as the value of crypto is too low you cannot afford even the electricity bill. Yes this is true because I've gone through this from the past 8months and I have stopped now also you need to invest lot of money in mining think multiple times and plan accordingly.