If you don't have a data plan, it would cost $0.05 per KB. You would need to switch your plan to a regular data plan. This would be your best option. To add data to a current rate plan, you would pay the following:
$25.00/month for 500 MB
$35.00/month for 1 GB
$50.00/month for 3 GB
$60.00/month for 5 GB
If you go over your limit and you have a Data Plan, it cost $0.05 per MB.