On a budget, weigh it — Het Scheepvaartmuseum (Maritime Museum) isn't cheap for what it is.
€18.50 adult, ~€10 child
A strong, kid-friendly museum where clambering aboard the replica East India ship makes the Golden Age vividly real. The adult taste call: the building itself — a vast 1656 admiralty arsenal around a glass-roofed courtyard — and the ship together do justify it, but the indoor galleries lean traditional. The smart move is to treat it as half a day on the Oosterdok: the Maritime Museum and NEMO next door share a waterfront, so adults get the architecture-and-ship hit and kids get two hands-on hours without backtracking.