A good place to check for cracks is the tail of the ski, which often is damaged by clunking the skis down on a hard surface. If a ski is cracked or glued, don't buy it. Also, check the bottom of the ski for gouges. If the bottom is rough, ask an expert if it is reparable. Skaters want a ski that is 10 to 15 centimeters shorter than a classical ski.
All skate skis are waxable skis.
The weight of the skier also is important here, so if there are experts or sales representatives around, ask their advice. Finally, for those who just can't make up their mind whether to classical or skate ski, there are combi skis, which should be about 5 or 10 centimeters shorter than classical skis. It's good for beginners trying to decide what they like. If they have a lot of fun doing either technique, they can always wait a few years and upgrade. Classical skiers can go with either binding, while skaters must go with the toe-clip binding.