If you don't plan to use your data much outside of your wifi coverage then it shouldn't be too much of a problem. 2GB of data could be overkill if you really don't plan on using your data outside of your wifi range. If you spend most of your time within accessible wifi range then you should be fine. It really depends where you are most of your time and what you use your phone for. 250-500MB of data are great if you don't really plan to surf the net much using data. This much data should allow you to check for the occasional weather update and maybe search something on the internet.
So unless you plan to stream videos from Youtube, Netflix, etc and/or spend a lot of time on social media then you should be fine with the minimal data...