HI,
As far as I can see you have to pay to get Pro (the full sets of icons),
The site concentrates on using FAS in a website (do you want to use it in a HTML project?) or on Desktop.
Not at all clear how you'd use it on Android (with a key to prove you'd paid?).
Not sure if they work in Android but I found
which has links to download Pro and Free, Web and Desktop, versions 6 and 5.
(download, add the ttf to your project/app as an asset, then use SetFontFile).