Find a better deal on wheels

THE DIFFERENCE in car rental rates is extraordinary. Big corporations can negotiate excellent deals with a single supplier, but for smaller businesses or self-employed people it pays to call several different agents. To find out the differences, we took three sample bookings: a one-way, one-day rental in a group A car from Cardiff to Manchester; a week's use of a mid-range saloon (a Mondeo or equivalent) based in Edinburgh; and a Tuesday-to-Thursday 48-hour hire of a classy Mercedes or similar.

THE DIFFERENCE in car rental rates is extraordinary. Big corporations can negotiate excellent deals with a single supplier, but for smaller businesses or self-employed people it pays to call several different agents. To find out the differences, we took three sample bookings: a one-way, one-day rental in a group A car from Cardiff to Manchester; a week's use of a mid-range saloon (a Mondeo or equivalent) based in Edinburgh; and a Tuesday-to-Thursday 48-hour hire of a classy Mercedes or similar.

For the first sample booking, the best deal was £44.50 from Avis, on a fully inclusive basis. Europcar could offer AA members a rate of £44.80 but non-members would have to cough up £56. Through Holiday Autos you'd pay £45 - if you could put up with the heavy background noise and distracted staff on the phone line - and with Alamo £48. After that the rates rise at a very steep gradient. Budget would charge £59, Hertz £62 (plus £6.50 for theft protection) and National Car Rental £73.38 (although this rate be a more reasonable £54.66 if you dropped the car off at the airport rather than in the centre of town). Apparently, Thrifty doesn't do one-way rentals.

For the second sample booking, hiring a mid-range saloon for a week in Edinburgh, your best offer would be from Budget, living up to its name with a rate of £148.50. Alamo would charge £160, Europcar £167.99, Thrifty £170, Sixt Sense £174 and National Car Rental £178.98. After that it's a hurtful £196 with Hertz and £215 with Holiday Autos. Most complicated of all - you have to answer a whole series of questions over the phone before they'll tell you the rate - is Avis. It charges £200 for the week (or £225 if you want to pick up your car in town rather than at the airport) plus £1.12 per day in tax.

On the last lap of our Grand Prix of sample bookings, booking a Mercedes - or a set of similarly snazzy wheels - for 48 hours between Tuesday and Thursday, the best rates were quoted by Alamo (£122.22) and National Car Rental (£125.99). Sadly, neither would actually get you a Mercedes, since neither company has any - you'd have to make do with a Vauxhall Omega.

For a chance of driving away with the real thing (though none of the companies could guarantee a Mercedes), the best deals were Budget (£144) and Avis (£148). Sixt Sense quoted £171, Europcar £186 and Hertz £228 (plus £6.50 for theft protection). Holiday Autos couldn't say whether or not the company hired out Mercedes, and Thrifty couldn't offer anything even vaguely similar.

Before you pick up the phone and start your journey into the world of car hire, you should also bear in mind that the differences don't stop with the price. Before you can hire a car, each company has various regulations about what age you must be, how long you've had your licence and whether you hold a personal credit card. If it's price that drives you, be flexible about times, dates and pick-up points, and check whether there are any special promotions before you book.

To book call: Alamo (0181-759 6200); Avis (0870 606 0100); Budget (0541 565 656); Holiday Autos (0990 300 453); Europcar (0870 607 5000); Hertz (0870 844 8844); National Car Rental (0870 400 4502); Sixt Sense (0845 600 6660) or Thrifty (01494 751 600)