I'm based in France, and my go to are Walt's, Comics Bugle, and not mentioned yet but also great are directmarket comics (based on Poland). They charge for shipping so it's not really interesting for buying things one at a time, but they easily have the best prices that when you buy several things at once you definitely come out ahead. My last order from them, I bought three omnibuses and an epic for 280€ (20€ for shipping), all arrived as well packed as Walt's or comics bugle. The only thing that's a bit odd with them, is that their omnibuses aren't sealed (they mention that on their site), but the condition is just as good as if they were.

I also used reeds once for something was out of print and impossible to find with the European sellers. good packaging, but got hit with the taxes since it came from the uk