Recommendations for light-weight walking/trekking shoes?

[JellicleCat]

Neither style nor beauty I know, but can anyone recommend a good pair of light-weight walking or trekking shoes? I need something robust enough to tackle a gorge walk, so more robust than trainers, but ideally I'd like to be able to wear them around towns for sight seeing too, so not too rugged. Must be light-weight as they are for using in Spain in the summer. Oh and preferably not costing a fortune either!