Is 500 mb internet enough for iphone?

Would 500mb internet enough for an iphone 4 a month? Ill be going on instagram quite a lot, bit of twitter, bit of safari and the odd youtube and ebay?

Honestly no. But if you're one who rarely uses the internet or apps you probably won't go over.

Probably not, I post a few pictures on Instagram a week and use safari a bit and I use 1 gb a month, if you have a plan where you get more data each month it will be okay as long as you're cautionary.

No, 1gb would be better to avoid over charges. I use a very little amount per month, but I turn my mobile data off.