"The agreed overall cost of the wedding was said to be around £20m altogether. Due to inflation, that’s probably around £22.3m in 2017. In addition, the extra public holiday for the event is estimated to have cost between £1.2m and £6m. This is due to the overall slow down in production." - The verdict
There has actually been a lot of controversy around this, the general public says that millions of pounds are needed for security alone, (arguably) this will come from the taxer.
Just a few months ago, the Grenfell disaster occurred in London where many lives were lost and homes were completely destroyed because "the council refused to pay an extra £5,000 for fireproof cladding."
You can probably guess why not everyone is excited about the royal wedding.