Spontaneous Europe Trip for $400

My roommate Noel and I went on a random trip to Europe because there was a flash sale on tickets to Europe for $380 (~$400 after tax).

So we went to Ibiza and Barcelona, with a layover in Amsterdam in the beginning. Along the way we AirBNBed with a view of a 700 year old fortress, ate tons of paella in Barcelona, and met some amazing people.