Star Wars 75234 - where to sell?

Try Adverts.ie or Bricklink - second hand value for an unopened set is closer to €80

They don't always sell on those platforms though, it's more like "whatever price popped into the sellers head" and sometimes, they do get lucky and someone might buy it at that price. It's never any harm to sanity check against specialist sites (like Bricklink) where there are more trades taking place, and the prices are a bit more down to earth