Unfortunately there really is not. The rates are calculated at US Postal Service (USPS) First Class International rates, which went up a few years ago and really have impacted how I'm able to ship packages abroad in past campaigns, my online shop, and anywhere else.
In the case of these deck, they're also heavy! The test print decks weight 9oz and that's with basic paper quality, plain box, and no extras. I'm expecting the final to be even sturdier.
Shipping to Canada, United Kingdom, and Australia is currently discounted for single decks (true cost is $8 more). It was actually miscalculation on my end that I decided to just leave as-is. It's fate? Hopefully this helps!