Best answer by Mayumi
Yes, you can.
You can change your plan once per billing cycle( and iy's free through self serve)
If you have a Tab plus plan, it's not that flexible:
you can switch your tab plus plan within them.
but if you want to switch to one of regular plan, then you have to pay off your Tab first to do it.
I wouldn't recommend Tab plus unless you need more than 7 GB data/mo.