Stephen Harper claims “The NDP, it's far from clear where they would get all this money to spend billions and billions of dollars at a time of economic uncertainty.”

Harper’s tax cutting agenda is far more costly than New Democrat proposals.

Cost of Conservative Promised Tax Cuts (in $ millions)

As economists note:

“If anything, the Harper tax cuts emulate a U.S. Republican ‘starve the beast’ strategy, in which tax cuts deplete surpluses, and deficits are fought by spending cuts — precisely the opposite direction that is required. This approach would only worsen the core economic problem and would do double damage by worsening inequality.”
– Economist Marc Lee, “How Resilient is the Federal Budget to an Economic Downturn?” Canadian Centre for Policy Alternatives, January 2008., p. 6.