I have two vehicles, can I use one FASTag for both?
Legally you cannot use one FASTag with two or more vehicles, you will have to buy two separate tag stickers for the two vehicles. FASTag is vehicle specific and once it is affixed to a vehicle, it cannot be transferred to another vehicle. FASTag stops working if you remove it from the windscreen as it damages the rfid circuit inside.
In any case if you happen to use the tag configured with one vehicle on the other, during regular audits if it is found that the tag and vehicle details are not matching, the tag will get black listed and it cannot be used again.
If you need to buy FASTag for your car, you can either physically buy one at POS Office at toll plazas, by carrying your identification as well as the vehicle registration documents with you. The KYC process is mandatory and this could perhaps be simpler as well while buying online through PayTM, Amazon. The banks that currently offer FASTags include HDFC Bank, ICICI Bank, State Bank of India, Kotak Mahindra Bank, Axis Bank, Airtel Payments Bank, Paytm Payments Bank and many more.