Paisaje Austral sells the four day trips that Punta Arenas is good for, at the lowest published prices I found for any of them. Fuerte Bulnes, the fort the Chilean state planted on the Strait in 1843 to claim it, is 40,000 pesos. Torres del Paine and back in a day — long, but it is the only way to see the park if the bus schedule has beaten you — is 90,000. Tierra del Fuego is 100,000. The walk out to the San Isidro lighthouse, the last building before Cabo Froward and the end of the continent, is 70,000.
They are on Monseñor Fagnano below Cerro de la Cruz, a short climb from the viewpoint everybody photographs the coloured roofs from. One mobile number, which is also the WhatsApp and also what is on their SERNATUR registration.