Barcelona's best hours cost nothing: Gaudí facades from the pavement, Bunkers del Carmel at sunset, Roman walls in the Gòtic. Add the free-Sunday museum window, a T-casual at €1.30 a ride and menús del día from €11, and three days run under €150.
Barcelona's central park opens 10:00 to sunset, free always. The 1888 Cascada fountain — young Gaudí worked on its rockwork as a student — anchors the north corner. Rowing boats €7 for 30 min if you splurge; the lawns cost nothing.
Four Corinthian columns of a 1st-century AD Roman temple stand in a Gothic courtyard behind an unmarked door. Run by MUHBA, entry is free Tue–Sun 10:00–19:00, Mon 10:00–14:00. Five minutes inside, and it reframes the whole Gòtic.
El Born's Carrer Montcada is free to walk end to end, medieval palaces on both sides. Bar del Pla at no. 30 does bombas and callos at €4–7 a plate; standing at the bar is cheapest and there's no cover charge.
The 14th-century Catalan Gothic basilica charges €10 for the guided rooftop but is free to enter for worship hours, roughly 09:00–13:00 and 17:00–20:30. Built in 55 years by port workers, it has the widest Gothic nave in Europe.
The 1882 iron market reopened in 2018 after a nine-year restoration that uncovered Roman road remains, visible free in the basement. Locals shop here, not tourists: fruit, jamón and cheese for a picnic run €6–9 total. Open Mon–Sat 08:00–20:00.
Carrer Blai's pedestrian strip runs on pintxos at €1–2 a stick, toothpick counted at the end. Nearby comedores serve a three-course menú del día with bread and a drink for €11–14 on weekdays — the single best value meal in the city.
Public outdoor escalators climb from Avinguda Miramar toward Montjuïc for free, saving the €13.50 cable car. Jardins de Laribal and the Font del Gat terraces cost nothing and give the whole port from above.
Carles Buïgas's 1929 fountain runs free light-and-water shows from the Plaça d'Espanya end of Avinguda Maria Cristina. Schedules shift by season — typically Thu–Sat evenings in summer, Fri–Sat in winter, and it pauses entirely in January and February.
A T-casual gives 10 metro/bus rides in Zone 1 for about €12.55, roughly €1.25 a trip versus €2.65 single. Ride to Alfons X, then bus 119 to the Turó de la Rovira anti-aircraft battery from 1937 — free, open-air, 360° over the whole city.
Barcelona's oldest garden, laid out in 1791, with a cypress hedge maze, neoclassical pavilions and a romantic canal. Entry is €2.23, and it's free every Wednesday and Sunday. Metro Mundet is a 10-minute walk; almost no foreign visitors.
The Palau Nacional holds the world's greatest Romanesque fresco collection, lifted from Pyrenean churches. Standard entry €12, but free every Saturday from 15:00 and on the first Sunday of the month — plus the rooftop terrace at €2 any day.
Walk the Rambla de Mar boardwalk to Barceloneta, past the 1888 Columbus column. The beach, the promenade and the Somorrostro breakwater cost nothing, and beach showers plus public fountains keep the day's spend at zero.