On a budget, Cannaregio & the Jewish Ghetto still earns its price.
Free to wander; synagogue tour / museum ~€12
Cannaregio is where Venetians actually live — long sunny canal-side fondamente lined with bacari (cicchetti bars), and the historic Jewish Ghetto, the very place the word comes from, with its tall tenements, five synagogues and a moving museum. The catch: it's a district to absorb slowly, not a single sight to tick, and the Ghetto's depth needs a guided synagogue tour to land.