Almeirim is a low-key Amazon river town, so the biggest budget levers are when you arrive (dry season, June–November, means calmer water, fewer rain delays, and easier day trips) and how you move between river points. Lodging is cheap by Brazilian standards—simple pousadas and homestays dominate—but every excursion price reflects fuel and small-motorboat charter costs, which fluctuate with the river level and distance to beaches, igarapés, or community sites.
Plan a daily rhythm of one paid anchor (a fishing excursion, a longer boat tour, or a guided community visit) and otherwise use free or near-free anchors: the riverfront (Rio Amazonas), Praia Fluvial de Almeirim, the Praça da Igreja Matriz, and slow walks through the bairro. Eat peixe frescal and tacacá at lunchtime (when prato feito portions are largest and cheapest) and carry water and snacks for river days, since stores close early and bottled drinks at the port add up.