Originally Posted by
USAFAN
I would drive to FRA. The rental company may charge you even with a fee...
Travelling to Frankfurt twice a week I would never ever drive. No way. Trains are fast, frequent and convenient and with gas at 2 Dollar per litre (this adds up to 20 Dollar gas for 100 km) trains can even be cheaper.
And as Germany is not the US, none of the big rental companies (like Sixt or Avis) charge you for domestic or "interstate" one way rents.