The site is not an exchange but they do have shiftlly's exchange widget which enables them to earn every time someone uses it to exchange funds. It's is my first time hearing about shiftlly. They've been featured to some reputable sites but I can't find a single user review about them hence why I would not recommend it.
If you wanna buy bitcoin, stick to reputable sites as said above. You can check the list here:
https://www.buybitcoinworldwide.com/. Take everything with a grain of salt and do your own research, you can also ask here.