Montenegro runs on the euro, but Kotor still hides a cheap trip inside an expensive-looking one. There is a free back route to the fortress, a €1 cat museum, market prosciutto for the price of a cruise-port coffee, and swimming that costs nothing at all.
The Austro-Hungarian mule track leaves the River Gate and switchbacks up to the ruined hamlet of Špiljari, where a gap in the old wall lets you into San Giovanni fortress from behind — no ticket booth on this side of the mountain.
St Luke's (1195) served Catholic and Orthodox congregations from two altars for 500 years, and its floor is paved with medieval gravestones. St Nicholas next door hides a silver iconostasis. Open roughly 08:00–19:00, no admission charge.
One room near Trg od Kina holds three centuries of cat postcards, war posters and enamel signs, funding the charity that sterilises Kotor's strays. Entry €1, roughly 10:00–18:00, and the lanes outside are where the actual cats hold court.
Where the Škurda torrent meets the bay below the north wall, locals swim off concrete slabs and flat rock. No entry fee and no sunbed touts, and the water runs cold where the mountain springs surface under the surface of the bay.
The daily market spreads along the seaward wall from about 07:00 and is busiest before 10:00. Njeguši prosciutto, sheep's cheese in oil, figs, pomegranates and village honey from Boka add up to two days of picnics for under €10.
The slice window on the main lane through the Old Town sells pizza by the cut for €2–2.50 and whole pies from €6, while the bakeries on Njegoševa do burek and cheese pastry for around €1.50. Eat standing rather than paying terrace prices.
Espresso at a table on the Square of Arms costs €1.20–1.50 and buys unlimited sitting time, which is the real Montenegrin unit of currency. Order domaća kafa for Turkish-style coffee at the same price and watch the cruise crowd drain away.
The big supermarket behind Kamelija mall sells Montenegrin Vranac from €3.50 a bottle, Nikšićko beer at about €0.90 and fresh bread for €0.60. Carry it to the grassy ledge outside the Gurdić Gate for a sunset dinner with a bay view.
Local buses leave Kotor bus station roughly every 30 minutes for the 20-minute run along the bay. Perast has no stop inside the village, so you are dropped on the main road and walk down; shuttle boats to Our Lady of the Rocks go when full.
Perast has sixteen baroque palaces and no through traffic, so the whole seafront works as a free open-air museum. Iron ladders drop straight off the promenade into deep clear water, and the pebble strip past the Bujović palace costs nothing.
The old shore road runs almost level from Kotor through the fishing village of Muo to Prčanj, about 5km one way, with the walls of Kotor framed across the water the whole way. Concrete swimming platforms line it, none of them charging.
Twenty-five hairpins of the abandoned imperial road climb behind the town, and the bend at roughly 500m altitude gives the postcard view over the bay and the Old Town roofs without paying the fortress entry fee.