Hi DeeDee - welcome back.

My route is a bit convaluted, but cheap. First Choice have a Saturday flight out of Gatwick to Salvador for about £260 return. From Salvador you can catch a cheap internal flight to Natal (or Fortaleza) with Gol airlines. Prices start from £30 each way (although you might have to go indirect) so that´s a return flight for close to £320 - it costs that much to fly to Spain sometimes!