Can anyone give recommendations on cheap car hire companies in Berlin? Looking to hire a car for a few days when parents comes over to visit in February.
I wouldn't worry much. Once you pick them up from the international airport just rent a vehicle from there. The prices are not cheap but competitive nonetheless.
Agree but personal recommendations would be of big help
It really does not matter which car rental or car for hire you choose on the airport and because they are coming from outside of Germany and that they will be picked up or you will meet them at the airport as I understand from your question. If you really want to make it more affordable, just ask the attendant if you could waive the other cost that they charge which you could and you also have the option to choose the vehicle which may be more affordable than the others. This is my personal recommendation.
Try this comparison website and pick your dates and pick up point.
This quick search turns up cars at €20 a day.
I hope this helps,
This list might come in handy.