I thought that was a pretty modest amount for an event on that scale too.
And those calling it a 'dressing up day' aren't as funny and clever as they think. It was a state occasion of historical significance. And as others have pointed out, the money was not 'wasted' in the sense that it will have gone into the pockets of so many artisan crafstpeople, event planners, security workers and the like. It probably made back money in tourism and 'soft power' too, though these are difficult to quantify.
To read some of the posts here, you'd think Charles and Camilla held a bonfire in the yards of BP and set fire to £70 million for the fun of it.
And saying 'I'd prefer if it went to the NHS' is a bit silly, because that's not the way state budgeting works.