Holy crap, already got a reply from Brad 18 minutes later even though it's Saturday 10:32 PM for him.
What basically happened was that Will from Barrister and Mann accidentally listed the soap for $17.99 on his website while his plan was to sell it for $18.99. Once he knew he made a mistake he decided to keep selling it for $17.99 and asked his retailers to drop the price to $17.99. Brad didn't realize a few orders got through at $18.99.
So to make up for it he gave me a code which grants this:
Value: $1, also grants free shipping (no minimum)
So, not only do I get a $1 coupon code, the code also grants me free shipping with no minimum order value. Now that's what I call
customer service!
EDIT (17/01/2020): yesterday I tried using the coupon code, it applied the $1 discount and said "free shipping", but still added shipping costs to the order. After contacting Maggard Razors they told me they made a mistake because they didn't realize I was an international customer. So they've changed the code to a flat $5 discount instead.