For all electrical items go to The Electrical Shop, (Euronics) in El Galan. Fantastic service, great after sales too. Very competative prices and better to support the smaller, independent shops that the big chain stores.
Second hand furniture and new small kitchen items go to New2you in Mar Azul.
Bedding Yorkshire Linen in La Zenia near Pets World.
Don't buy electrical stuff, not even light bulbs, in the chinese discount stores. They are great, however, for reasonably priced outside cushions, soft furnishings, oven tins and loads of other bits and bobs.
There is a sofa shop and bed shop in the older shopping centre just off the N332 in La Zenia, near Paddy's point. Very helpful. There are two bed shops there and one is much cheaper than the other. However if you already have bed frames just buy new mattresses. If you need to replace the bed frames there are loads going second hand. New mattresses at good prices also available at New2you in Mar Azul.