We r going to Villanova, just outside Barcelona costs 5 euro by bus to get in to centre. Costs are so reasonable.
Make sure bedding is inc, some sites you have to bring your own which on a plane is a bit hard
they also have bekse bergen Netherlands) available which looks a great campsite and included passes to local attractions included safari Park etc but only for 5people but price starts at €129 for long weekends. we will book direct next year's this site and it will be about €800 for a villa with hot tub for a week, then drive over on shuttle and drive upto it (think about 3 hour drive from calais through Belgium.
check out Groupon.nl and europamps are listed on thier, for different countries, France starts at €99 for 7 days for 6 people fir example. whilst they have restricted some dates when I checked some dates in our school holidays were available
This isn't for a tent though its for a 2 bed static caravan with decking and air-conditioning. Ive stayed at this site with eurocamp in a 2 bed van and had a fab time. We are booking again for next summer as we going to Lake Garda with canvas holidays this summer. You can stay in tents as well but this deal should be mice free!! They do a bus from the gates into Barcelona which is a lovely city. We did hire a car tho as we self catered and for days out.