I was browsing through flights to Barcelona with Vueling and discovered this! There are flights from Birmingham to Barcelona for as little as £4.42 each way (you must pay a €10 admin fee as well)! There are lots of weekend flights available too! I'm not sure if it's an error or what but don't hesitate - just book!
Use code UKFLYNDER for 10 EUR off each passenger!
Not an error, it's on vuelings front page
Also offer ends today 19/01/2017