I can answer about France: more or less 1Euro or 1,10Euro for a liter. The cheaper one, red colour, is for heating or professionnals. You can try but take care about controls.
Have a nice trip in France!
Dominique
MY BALDER VII
Talking of French controls, be careful of what you're getting! I asked a French lock keeper to arrange a fuel bowser delivery whilst in a remote village on the Canal De La Somme, and we didn't realise we had taken on 120 gallons of GREEN diesel until the tank overflowed! This is highly illegal stuff and we could have got into very serious trouble had it been spotted. We were happy to pay him the miniscule price demanded though....
In France, what we do is go to the local garage..I know it can be difficult etc. etc. but if you can arrange for a stop near a supermarket diesel is still under a Euro while some marinas are now getting to €1.30
If you are in Torrevieja the garages round you will be the cheapest you will find on your travels.
We used an old wheeled suitcase and a plastic jerry can and each time we went for a walk we filled up the can. Doesn't take long, you know it is clean diesel and you have saved quite few pennies by the end of your trip...or am I just being tight?
When we left UK we first of all took car to L'Havre and left her there with 200 litres of red diesel in the boot.!!
You will get asked if you want to buy diesel and when we said yes we got a receipt from the local Mayor!