Definitively a place to check yeah.I've been there, but went with family and didn't take any notice of where I was shopping. Try checking with your neighbours. If you're not a smoker and you have a neighbour who is, expect to be asked to bring cigarettes back
Alcohol, tobacco products and food are all generally much cheaper there, irrespective of where you shop. If you are purchasing alcohol or tobacco, make sure you stay within the allowance as they are doing far more checks now.
It's well worth thinking about making it a bit of a touring day, taking different routes there and back - the landscapes are stunning, especially if you get off the major road.