1 month payment plan for phone?

So I'm not a big fan of smartphones so I have an ancient keyboard slide up phone as my phone that I use to text and call people. I have an iPhone 5c for my social media purposes when I have Wi-Fi and I'm going to myrtle beach in august for my birthday with a friend and her family however I want to use my iPhone as an activated phone using my phone number for just that month. I was wondering how that's possible with a prepaid thing? I'd want unlimited data though so I can use my social media when I don't have Wi-Fi access. How would that work and would that be expensive like over $50 ?

Look into walmart unlimited Straight Talk plans

Your iPhone needs to be on the same network carrier (GSM or CDMA) as your prepaid, and the iPhone needs to be unlocked.
then you need to discuss it with your prepaid provider. There may be an additional fee…