Flight cost: £21.98 return.
Accommodation cost: £158.20 return.
Food:
Everything else: 
Total: 

Flight details: Return flights with Ryanair from Manchester to Madrid were £21.98. Flying out on 24 January 2018, returning on 27 January 2018.
Accommodation details: I rented a small flat for £158.20 through Airbnb. Because I had Grace with me, the requirements were for more space than usual, and also somewhere relatively quiet. We stayed at La Paloma, which is in a great location – there’s a good sized supermarket just around the corner, a cafe at the end of the road and Puerta de Toledo is a couple of minutes walk.