Lots of companies offer unlimited plans. A tablet is really just an oversize smartphone as far as the guts are concerned. If the tablet has hotspot capability, it's purely up to the data plan you have...and assumes it's compatible with the cell companies system.
Generally, the unlimited plans have a couple of catches:
- Check if it includes the hot spot. Sometimes it's extra to activate the hotspot and/or has a separate limit for hot spot data.
- After a certain limit, they will typically throttle the data. You can still use the data but it slows down. If you get to extreme levels of data usage, they may even drop you as a customer.
