Yes a decent manufactured vice is pretty much a lifetime item, but look online for home-made ski vices. You can make a very serviceable vice out of a single 6' 2x6 with a few well placed cuts, L brackets, and screws. Spend a few minutes googling and I think you will find some fine examples. Eg.
Mount to a base and a couple C clamps and you are in business.
HINT! Once you have your wooden supports, glue or staple on some strips of mouse-pads RUBBER SIDE UP. This keeps the ski from moving around excessively.
One of he common misconceptions about tuning is that the ski has to be clamped down super tight. Unless you are setting new edge or base bevels and removing all kinds of material, the rubber grips will hold the ski sufficiently for regular tuning and waxing. A light touch with sharp files is all you need. I rarely clamp in my skis when working on them.
I piece of paracord looped around the binding and tied tightly enough to the bench to slightly flex the ski clamps it down firmly. Wanna be fancy? Screw a small boat cleat to the bench for securing the cord.