Possibly the most popular is the Benicassim International Festival in Spain. This is a lovely venue quite close to both Barcelona and Valencia, and in 2012 tickets cost under 200 euros for 4 days, including the fees for the campsite. Tickets are already on sale for July 2013; in 2012 the acts included the Stone Roses, Florence and the Machine and even Bob Dylan.
In Hungary, the Sziget Festival in Budapest was a big hit last year. One attraction is that it lasts for a whole week and there are all sorts of other things going on as well, such as sports and cinema facilities, so some people make a holiday of it. The ticket price again should be under 200 euros, and you can also buy a day ticket for about 40.
For something different, there is the alternative music festival in Meerhout, Belgium. You can camp on site or stay in nearby Antwerp, and fans are invited to send in suggestions for the bands they would like to see.
You can find more ideas for 2013 festivals here.
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