EDIT: Ahh, yes, I see what you are talking about now. Probably AT&T's data plan, right? 200mb is not much at all. Stay far away from YouTube or any other streaming video or music services when on wireless connection. You could burn up 200mb of data transfer in 2 days if that if you were sitting around watching YouTube. Don't download any apps when you are not on WiFi. Really, try not to even use any of the data, because your phone will probably use some automatically as you travel around. If you want to be out and about and use your smart phone, you really need to the 2gb plan (or just a higher plan if you are on some service besides AT&T). My wife has the 200mb plan, and she had to disable her phone from making automatic updates. She uses it maybe once a week or so to look up a price online or check weather or traffic. That is it. You can't do much more than that without a higher plan.
Original: Today, 200mb is almost nothing. Some smart watches have at least 1gb of data.
If you aren't familiar with the terms, mb is Megabyte, which is 1 million bytes. In modern computers, a single letter of writing takes 2 bytes (in Unicode, which is the more common encoding format today; only 1 byte is needed for ASCII, but ASCII cannot display many foreign alphabets, whereas Unicode can, which is why it is preferred). So if you were only storing "plain text" text files (like .txt files on Windows), a mb should be able to handle about 500,000 characters. 200mb is 1/5 of 1 gigabyte (1 billion bytes). An average modern smart phone has storage of between 8 - 64 GIGAbytes, or many times that 200mb.
It sounds like a lot, but things change dramatically when you start looking at modern computer usage and realize that almost any device is going to be storing music, sounds, graphics, video, etc. Those burn up storage much faster. An average MP3 song is around 3 - 5mb, depending on length and quality. So that 200mb would hold about 50 MP3s.
Video takes up much more space. A standard resolution (no HD, not even 720p) movie file for a typical length movie (about 100 - 110 minutes) will take up about 700mb, or several times more than that 200mb. If you want to start talking about full 1080p HD, a regular length movie could take up to 9gb, or 45x more than that 200mb.
So the short answer is that it is a little. Not a lot. :)
Programmer for years and AT&T smart phone user