The bits of Jingle Jon’s argument are the fact the trucks are paying tolls so in essence the parking is not free, well unless you are an owner operator do the tolls effect your wallet?
Also I don’t find it an issue paying 50 cents for a ■■■■ and getting a voucher to use in the services for 50 cents.
From what I have seen though in my limited time in Europe is there is loads of massive parking areas off the main roads for free, services that are free and then truckstops where the most I have paid so far was €10 but I got a €10 meal voucher. In France the Routiers are free parking but you do have to go in and buy a meal.