Is 500 mb good enough for me? Or y iPhone 4S?

I'm aware that its not a lot, but will it be enough. It kinda has to be. For its expensive. I watch some YouTube, but the majority will be on Wi-Fi. And I will probably go on Facebook quite a bit. But a lot of will be on Wi-Fi. I'm not one for checking email.

1 minute of Standard Definition (SD) is about 2-3 mb. Facebook is much better on the data. 50 fb pages takes about 5 mb of data. 10mb is 1 minute of hd video on youtube

Should be allright, most people say that 500mb is only good enough if you check your email and go on social network sites the only problem i notice is when you watch videos over 3g the quality usually decreases a lot. If you want you can get your contract capped so you don't go over your limit