Got new iphone and it already has 1.5 gb of other?

So i got a free iphone 4 with my new phone deal and i was just registering it and putting music into it when i noticed that the "other" thing is 1.5 gb. I haven't even downloaded anything onto my phone. Can someone tell me what this "other" thing is and how to get rid of it or atleast lessen the usage. Please help. I only have a little bit storage left because of it. Also if i don't buy the internet and use my own Wi-Fi and get apps and use i message and youtube and search stuff will it cost me money? My cousin told me something about it costing money to use your own Wi-Fi? I think hes lying tho.

Other is the stuff that actually makes the iPhone, iPhone. Your forgetting camera, calendar, notes and more.those things are other. It's only a bit of space nothing too much.

Other is any files that the iPhone uses to work. Like ios or any documents. You should have it checked because other should not be that big this early.
When you use Wi-Fi without data then it should be free accounting that you pay the Internet. You can put your phone on airplane mode with Wi-Fi on to make sure you don't use data.