I thought this is just normal thing, that you can bring your SIM card anywhere and it will just work. Prices are different thing. The device could be optimized

I thought this is just normal thing, that you can bring your SIM card anywhere and it will just work. Prices are different thing. The device could be optimized to send the data only when connected to a low-cost network, or send just general data at very low frequency when on high-cost network, just to know the device is alive. Also getting a cheap plan on data but expensive on calls should be also possible.