We considered getting a full sized washing machine but we just don't have the space! We don't mind doing sheets and adult clothes once a week in the communal machine.
When I look up mini lave linge on amazon.fr, this is a selection of the machines that come up. http://www.amazon.fr/s/ref=nb_sb_ss_...ini+lave+linge
It looks like the portable ones mostly wash around 1 kilo, and are the kind of thing you could put on a counter top or take on vacation. They also tend to be under 1000 euros. I'm concerned though, that they might be weak, little more than glorified salad spinners.
The mini washing machines that look more like regular washing machines cost almost as much as the full size.