Now, I'll illustrate certain effects of taxation; these are approximate.
Roughly - U.S. Federal Tax on spirits is 1/4 the Federal rate here.
Since someone used Vegas as an example, the City+State sales tax in Vegas is 8.38%, while the rate in Toronto would be 13% HST.
If we harmonized at the U.S. rates for the example above.
The landed cost drops to ~$8.12
To which you then apply the LCBO mark up of 139% to get $11.28 + $8.12 for a total of $20.40
Then we add the domestic charges for volume levy and env. .38c for $20.78
You then factor the sales taxes. Apply the lower rate of 8.38%
Which gives you a grand total of $22.32
The remaining price difference is largely the LCBO's mark-up.
That mark up in the U.S would vary widely, but likely be the range of 50% on mid-range product. (as opposed to 139%)
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If we go back and adjust the mark-up to 50%
You lower the retail price to $18.12
Needless to say if you find a discount liquor shop, where the markup might be as low as 30% in a state with no sales tax the price would drop further still.