Espargos is Sal's actual capital — the largest town on the island and the main residential centre, sitting in the middle of the island near the airport. It's a working town rather than a resort, which makes it a more authentic alternative to Santa Maria for visitors who want to see how Sal actually lives.
The central square and market area have cafes, supermarkets, and a good selection of local restaurants serving cachupa (the national stew of maize, beans, and whatever protein is available). Prices are generally lower than in Santa Maria. Espargos is the practical base for exploring the north and centre of the island, including Pedra de Lume.