Do you just need the gate & motor or will you need the trench as well ' ( for the track it runs on )
Prices depend on area. Gate prices should be around 100€ a m2 , so a 6m x 2 m would be 1200 €'s. Motor installation 800€ , to include installation of toothed rack ,motor , photo-cells, 2 remotes, assuming track was already there & access pipe to both side for the photo -cell wiring.
Obviously that's for a standard gate . If you want something really fancy, or built out of extra thick tube , etc, etc , the price would rise accordingly.