insurance company surplus

What is the best for the car rental company in the UK?
I'm 23 and am looking to rent a car for a weekend in December to move my things back home UNI (as I am pretty sure it should be 25 to rent a van) and need one that allows different pick and leave places. Can anyone recommend a company and say and what kind of charges will apply other than rental costs + surplus possible for my age (eg is an additional charge for insurance if not currently have a car of mine?) Any advice would be appreciated as my own research has not produced anything remotely Affordable!
You will need a rental company large (Hertz, National Car Rental, Europcar, etc.) to leave your car in a different place. You may be able to haggle a price, if you ask about a car during the weekend. It's his downtime.
Captain Blue Shield – Pirates of the Health Care-ibbean