Mobile phone help please

On GB of data.
1/ Unlimited data. Do they have a fair usage ?
2/ 1 GB of data. Do you get a lot of Internet with this ?
3/ Is 2GB of data to small for 4G ?
Getting two phones a iPhone 5s for the boy. And a I phone 6 for me but it's the different deals with the data I am trying to get my head round.
Thanks for anyone that can advise

I have 7gb
more than enough and it's 4g

Think you can share data usage as well.

Around 7GB is perfect for you and your nipper, recently upgraded my phone for iPhone 5 on TMobile and because TMobile are now EE I had to move from a 3g plan on Unlimited data to a 6.5gb data cap and was quite warey, but I don't even use any where near that. just remember to turn you 4g off when not using it as it can drain battery and your data (Y)

I'm with 3 network and have unlimited data. It's exactly as it says, I can use as much internet as and when I want. Not sure if it's the same with other providers though.