I do lots of research. I go directly to the car rental companies and then compare on other sites like Kayak or Hotwire. Sometimes it's cheaper either way. And the prices change all the time depending how early you reserve. I really got snookered though when I used Economy Bookings. Beware of this company. They are bad news.

Economy Bookings lures people in with a great price - then fails to deliver.

Sometimes 'bargains' come with a hefty price...

Having learned the lesson the hard way, I would go direct. Companies like Economy Bookings represent nothing more than another layer of administration and cost. I thought I'd be saving money when I rented from them in Europe but I ended up spending more time and money than if I had gone directly through the car rental company