It is often a constitutional convention that the upper house may not block a money bill. There is often another requirement that non-money bill - type clauses may not be attached to a money bill. The rationale behind this convention is that the upper house, being appointed or indirectly elected, should not have any right to decide on taxation and public expenditure - related policies as may be framed by the directly elected representatives of the lower house. Therefore, money bills are an exception to the general rule that for a bill to be enacted into a law, it has to be approved by both Houses of the Parliament -- the lower house and the upper house.
the dominant role in passing a money bill is vested in the
lower house lower house