GOING ABROAD WITH AN IPHONE4S?

I have a iphone 4s i'm going abroad tonight.
I like using apps such as instagram facebook and snapchat. Do i have to keep mobile data turned off when i have a Wi-Fi or on please tell me what to do?

3 options

buy a data bundle from your network and stick to the amount of data you buy

turn off data roaming and only use Wi-Fi

pay through the nose for data roaming