There is a much better way to accomplish what you mentioned in your post.
T-Mobile isn't the best way.
Unfortunately I will not advertise for other carriers .
Try another carrier for a low cost alternative.
According to this Pay in Advance (Prepaid) plans under "Pay As You Go" plan, here's what you can get
optional data passes:
- 1-day 500 MB data pass for $5
- 1-week 1 GB data pass for $10
(this pass is good for 7 days)
Yes you can add data pass from your desktop by logging-in to your T-Mobile online acct.