I agree that Labour was throwing money at people to get votes. Which is basically what always happens in elections in peacetime (except perhaps during a financial crisis). But a few things:
a) Tories didn't bother to cost their manifesto at all, and hence didn't really have a leg to stand on when challenging it
b) Tories barely bothered to challenge it, nor highlight that they would be better for the economy, a traditional campaigning point.
This is second one is likely because, the Tories aren't for the economy anymore, since they favour hard brexit and are threatening to make it worse with this no deal nonsense. Labour, while hardly much better, are at least not threatening to shoot the economy for ill defined reasons. 
So people who might feel that a stronger economy means better public spending options could no longer think the Tories have a leg to stand on here. 
Also, leaving the single market is pretty starkly against thatchers legacy.