Upvote:13
Thailand does not care how much you take out of the country, you've bought them legally and what you do with them is not their business. If you want to know Bangkok airport duty free prices, just call up King Power, who has the monopoly: https://www.kingpower.com/en/
Your problem is going to be Customs on the EU side. You can legally bring in over the duty-free limit if you declare and pay duty... but, of course, this will mean they cost more or less as they do at home.