It usually takes 2 billing cycles to switch the supplier and get the new supply rate on your bill i.e. you sign a contract in January with a start date of successive month (February), then you’ll receive the first bill on new rate in March (upon completion of a complete meter reading cycle of February).

There is no enrollment or registration fee but termination fees can occur if it is stated in your contract and it usually varies from supplier to supplier. The suppliers usually charge termination fee to cover the damages as they have to find a new customer to reassign the volume of electricity that you were supposed to use over the remaining term of contract.

There is no front end changing like meter or wires replacement at your service address as the switching of supply services occurs at backend between utility company and supplier.

Yes, but it depends upon various factors i.e. partial/complete gas deregulation in your state, minimum gas usage volume requirement set by the suppliers to bid.