Difference between a courtesy car

The running costs of these vehicles need to be paid so why wouldn't you as the user expect to pay this cost.?
Perhaps I'm over cynical but it seems that people take a lot more care of something they have to pay for than a "freebee"
Also you can bet your booties the car is returned on time when the job is finished not days later when they decide to call in for their repaired car.

You think they should pay for your petrol while you go gallivanting all over the region too? It isn't a matter of just giving someone a car. That very car has to be warranted (now garages aren't supposed to do their own warrants), insured, registered, maintained, repaired, filled with petrol, cleaned (because a lot of users treat 'courtesy' cars as rubbish tips) and someone moans because they have to pay a fee? Get a taxi and then see which one you would prefer.

I always return their car on time, I would rather be driving around in my own car than a car that needs detailing (cleaning inside) so I am very happy to get my car back. The garages should say if it's a courtesy car or they are going to rent it to you (charging you for it) Every time I have got a car from a garage whether it was a courtesy car or a car rented to me the petrol gauge is always on empty so we are paying for it in more ways than one.

"There's no such thing as a free lunch". A 'free' courtesy car is simply paid for from a higher mechanics rate/parts surcharge etc etc. some people don't 'get' this, much like some people thing 'free healthcare' just happens, rather than being paid for via tax.

However, there are two approaches a business can take: Advertise it as a 'free' courtesy car (and simply incorporate costs into a higher charge for any work done) or charge it separately (benefiting people who don't need to use the courtesy car via a lower charge on any work done). Which approach to take depends on your clientele.

You want try working for Insurance Co's mate.
They expect you to supply your customer/their client with a car, whilst they pay an hourly rate of $60. There's no margin for a surcharge in there.