Will 100 mb of data be enough?

I'm getting an iphone 4s and it comes with a 100 mb data plan, i won't be using my phone for much else apart from the facebook app, will this be enough?

Absolutely.

Note that if you decide to download apps, this can easily hit your 100 cap. And of course, if you stream music from internet radio… It's nearly 50mb an hour, and that's just at 128kb/sec which is the low quality for most sites.

So indeed, 100 is enough for facebook, mail, calendaring, etc. And just set it to always connect to local Wi-Fi networks when available, that way you can ease-off the data plan when you can. Enjoy your phone.

Absolutely fine, facebook uses no internet at all and so 100mb won't even be touched. I would also go as far as saying you could watch entire movies constantly day after day on your data plan without having to worry. The iPhone has a data compressor band that squashes all incoming data to near immeasurable amounts. You will be fine, you'll be fine, I wouldn't worry, don't worry… Worry a little.