The total cost with pre pay shipping Will be 86 usd for an Invicta 8932 that normally cost 53 usd. Because I have to ship to Denmark it gets quite expensive. I wonder if this is even worth it for such a normally cheap watch? I can also choose pay later for a total cost of 76 usd, but I think it Will just give more trouble. Is there any coupons or something I can use or should I just not do it?
Duty is there to discourage you from doing exactly this. Your country is using “the stick” to get you to buy locally. If it’s available locally, you may pay more, but you’ll avoid duty.
Do you still pay duty on items within the EU? If not, maybe you can find an EU seller.
There are no custom charges between EU countries. I'm sure op will find something.