Vatican City itself charges for exactly two things: the Museums and the Dome lift. Everything else — the largest church on earth, the papal Angelus, the Swiss Guard changeover — is free. Sleep and eat in Prati or Trionfale next door and three days cost very little.
Entry to the Basilica is permanently free — no ticket, no booking. Open 07:00–19:10 April–September, 07:00–18:30 October–March. Join the security line under the right-hand colonnade by 08:30 and you are inside in 20 minutes; by 11:00 the same queue wraps the square. Knees and shoulders covered.
The Pontifical Swiss Guard swap sentries at the Porta Sant'Anna gate on Via di Porta Angelica roughly every two hours, with the fuller relief around midday. Halberds, Renaissance-striped uniforms, no barriers and no ticket — you stand on the public pavement a metre away.
The Passetto, the 800m fortified corridor Popes used to flee to Castel Sant'Angelo, runs along Borgo Sant'Angelo. Walking its base costs nothing and the raised stretch near Vicolo del Campanile gives free sightlines over Vatican rooftops that tour groups pay to approach.
Bernini's ten angels line this pedestrian-only 2nd-century bridge, free and open around the clock. Walk west up Via della Conciliazione at dusk and Michelangelo's dome grows steadily larger — the composition Mussolini's demolitions created in 1936.
Rome's largest covered market, roughly 270 stalls, ten minutes' walk north of the Vatican walls. Open Monday–Saturday about 07:00–14:00. Pecorino, mortadella, tomatoes and fruit at resident prices; a full picnic for two runs €8–12 rather than the €25 of Borgo Pio cafés.
Gabriele Bonci's standing-room pizza al taglio counter, one metro stop from the Museums at Cipro. Sold by weight — point at a tray, they cut and weigh it, and a filling slab lands around €5–7. No seats, no cover charge, no service fee.
Italian law posts two prices: al banco (standing) and al tavolo (seated). Drink your espresso standing at the counter in the Borgo Pio bars and it is €1–1.20; the same cup at an outdoor table on Via della Conciliazione is €4–6 with coperto.
Prati's neighbourhood forni sell pizza bianca, supplì and focaccia by the etto until roughly 20:00. Two supplì and a wedge of pizza rossa is dinner for about €4. Eat it on the free benches of Piazza Risorgimento facing the Vatican walls.
The Museums and Sistine Chapel open free on the final Sunday of each month, 09:00–14:00, last entry 12:30, no booking possible. Queues start forming on Viale Vaticano before 07:30. Any other day it is €20 online plus a €5 reservation fee.
Every Sunday at noon the Pope appears at the third-floor library window on the square's right side for the Angelus, about fifteen minutes. Completely free and unticketed — walk in. Wednesday General Audiences also cost nothing but do require a free ticket from the Prefecture.
Rome's 2,500 cast-iron nasoni pour free, cold, drinkable water; several stand inside St. Peter's Square and along Via di Porta Angelica. Fill a bottle here instead of paying €2.50 at kiosks. The yellow Vatican post boxes need Vatican stamps, sold at the square's post office from €1.30.
A free public terrace 20 minutes' uphill walk from the Vatican, with the dome, the Tiber and the whole historic centre laid out below. A cannon is fired at noon daily. No entry gate, no closing time, and far emptier at sunset than the paid Dome climb.