Before going to a festival I usually buy half of Penneys because for one it's so affordable that if anything gets ruined from rain/mud it doesn't matter as much as something more expensive. They are one of those shops that carry mostly on trend, seasonal collections, so you'll be as stylish as the celebs in Coachella. Their accessories are great too!
This year Penneys are setting up a pop up store 2000 sq ft down at oxegen go if you forgot anything or just fancy something new to wear to Swedish House Mafia you're in luck. I'd suggest picking up a bottle of their tan, St. Moritz. The dupe to St. Tropez and at only €3.99 far better value. I have heard nothing but great things about this tan and I've researched it A LOT! Everyone is telling me try it. Do apply it before you head off because without the morning after shower reports are you'll just look dirty but it is great to build up!