I have been using the cheapest plan ($28) with my iphone 4 since 2013 without any data included. I'm using my phone mostly in wifi so I don't really need to change my plan.
As I know, data booster cannot be added to a monthly plan user.
Then, is there anything else that I can do for my temporary data usage?
I just need some data when I'm not in wifi-zone while traveling in another province for a few weeks.