If you're skiing on a budget you can't go far wrong with Snugpak's 2nd Skinz long johns, whose loose, comfortable cut makes them versatile enough to use for any other cold weather outdoor activity that doesn't require a skintight outer layer.
They're made from Coolmax fabric which uses superfine internal 'hairs' (don't worry, they're not itchy) to search for excess moisture, which is then absorbed and wicked over a larger surface area. These same hairs trap air too, thus keeping your body warm when cold and assisting with cooling when it starts to overheat.
The design is as simple as it gets, with an elasticated waist and elasticated cuffs being about the only technical features you'll encounter. Crucially they're a fifth of the price of the super-technical X-Bionic long johns that we reviewed elsewhere, and for a good number of recreational skiers and boarders that alone will be enough to win them over.
You even get a useful little zipped carry pouch with the long johns that will easily stand in as a mini toilet bag or just a useful means of carrying stuff in your pack when skiing, such as sun cream and energy bars; what's not to like at less than twenty quid?