How much data do i need on the iphone 5?

I'm getting an iphone 5 and was wondering how much data i need per month for my plan? I don't use my phone to download apps or watch videos or listen to music. I do that at home on my computer or on my phone but using my home Wi-Fi, not 4g. I only use my phone heavily for twitter (Like 15 tweets a day and refresh the feed like 10-15 times a day) facebook (Post 1 status, refresh feed twice a day) Instagram (Post 1 pic a day and refresh feed 1-2 times) i also occasionally use the maps app to navigate to places but i only use it around 1-2 times per week

Is 100mb or 200mb enough?

Start with 100 mb and use it normally. If you see you need more, then switch to the higher plan the next month.

I think 1-3 gb should be enough for you as you said you use your phone for social media and maps. I will tell you if you navigate from your phone for 2 hours, you will use about 5 mb-7 mb of data. So maps don't use much data but i don't know about facebook, twitter and instagram. You should try 300 mb and if you find yourself exceding that limit, you can always upgrade to more data. You should try 300 mb.