Is 200 MB of 3G/4G on my iPhone enough for 13 days on T-Mobile?

T-Mobile has a pay by the day option for $3/day unlimited text, calls, and data. The first 200 mb of data are 4G/3G and then after that it's 2G. I want to be able to occasionally check my email, use maps when I get horribly lost, and maybe check facebook when i'm away from Wi-Fi. Is 200 mb will be enough for just 13 days? Or will I eventually be only able to use 2G?

It depends TOTALLY on your actions. If you just check email, yeah it should be enough. But there's so much to do on Facebook that it varies data use wildly. If you just check posts, it won't take much at all, but if you start flipping through pictures it will be a lot more, Videos of course will totally eat that up in a very very short time.

An iPhone uses almost twice as much data as any other device you can get, aside from a Laptop. It always requests full internet pages, and updates them by itself, So the data it uses is pretty hefty. Maps can be heavy drain too, if you use them for more than a few minutes.

If you are very very careful it will last, but you will have to watch closely what you do.