Want to play FFXIV? Of course you do, thats why your here! Anyway you'll be buying Crysta tomorrow so you can play.
What is Crysta? Well its like MS points that you use on Xbox Live but these points are used for paying for FFXIV sub and security tokens. Being an English man myself, I am going to quote the exchange rate for proper money here, £1 = 100 Crysta Points. You can convert that into whatever funny money you have in your place of residence!
Either way buy points to play game, thats the bottom line.
Why not read what CVG had to say about the issue here.