What iPhone data plan do I need?

I'm looking into getting an iPhone 5 (or maybe 5S) and I'm wondering what data plan would suit me best. I will probably be using data mostly for social media (Facebook, Twitter), mail, and web browsing. I'm looking to save as much money as I can, so I was thinking of going for either a 500 MB or 1 GB plan. Will that be enough, or should I think of going bigger? As a note, I won't be using data too much cause there's free Wi-Fi at my college.

If you're able to stay on Wi-Fi most of the time 500MB should be enough.

Just don't watch videos while using data.