Verdict: Madrid is easy to do well on a budget — pair free museum hours with walking and the midday menu del día to see art, parks and nightlife in two days. • Free hours: the Prado is free daily 6–8 PM, Reina Sofía free Mon & Wed–Sat 7–9 PM (Sun 12:30–2:30 PM), the Thyssen free Mondays 12–4 PM; the Royal Palace is free Mon–Thu (5–7 PM Apr–Sep, 4–6 PM Oct–Mar). • Cheap eats: have the menu del día (a €12–15 set lunch with starter, main, bread, drink and dessert); skip plaza cafés for breakfast and save €5–7 at a neighbourhood bakery. • Free must-dos: Retiro Park and the Crystal Palace, the Temple of Debod at sunset, and the El Corte Inglés rooftop viewpoint on Gran Vía. • Skip the €100 flamenco shows — smaller venues like Las Carboneras or Essential Flamenco feel more authentic; most sights are a 20–30 minute walk, and don't miss El Rastro flea market on Sundays.