Virgin mobile prepaid or Verizon?

ok well I currently have a virgin mobile prepaid phone(The oyster)...I have a Verizon prepaid phone also but I stopped using it because I heard and figured that Virgin mobile was cheaper..because you didnt have to pay 99 cents a day even if you didn't use it. Well now i've been thinking about switching back to Verizon because I just read on verizonwirless.com that you can pay 99 cents only when you use it. So now I think that would be better. On Virgin I changed my plan to so minute plan that i pay $20 all the time every 90 days. i'm 14 so..