Cryptocurrency,, -- Which to Invest in?

As seen in the image above,, a friend of mine on whatsapp said he has $50 and wants to invest in bitcoin.. So he ask me yesterday which to invest in..

The problem now is,, I'm into cryptocurrency too but in the hub I'm in,, we only allow minimum investment of 100$ ...

So if you have or know of a reliable and sure crypto-currency platforms Pls send links via the comment box..

And please don't give me unreliable site.. I would not have my friend loose his money...

Please Please Please!! No Fake site..
Thanks!