Well, it's not always the case that money is paid up front.
Who pays plumbers, electricians, plasterers etc for quotes?, Very few I suspect.
What about estate agents?, again, no money up front, but they incur costs.
My own buisness, kitchen manufacture and fitted furniture... I have lost customers when I suggested that I couldn't travel 50 miles for free in order to discuss their job in their house... if they wish a free quote they can email me basic info, or visit my workshop.. but some customers refuse, and get peeved off when I refuse to do house calls for free.
(I'd try to charge a fee just to cover my costs to call into people, i.e 60 or 80 Euros perhaps, and this'd be taken off the bill if they go ahead.)
It's the same with kitchen quotes... does anyone pay for those? I suspect very few do... I have many customers who turn up with practically no information, and they expect me to quote for free based on incomplete info.
So a garage could also reasonably be expected to provide a quote for free, and if that involves them examining the car then yes, that should be free. Or it could be free, if they wished.
If everythings is agreed beforehand then fine... but if no payment was mentioned before hand then it's a bit rich to try to charge now.
Do people think a garage should be paid for discussing the new cars they have for sale with a potential customer? Should they charge for test drives?
If not, then why all the 'time is money' and 'the garage is not a charity' statements... all companies must carry out some work for free., or should carry out some work for free, depending on the business model.