When talkiing to skiers about waxing skis, amazinly the topic can get quite polarized. What I find most amazing is most skiers do not wax and many that do, only do so occasionally. Some even flaunt the fact that they never have had their skis waxed. Mmmmm...do not really want to get into that right now.
Search around and you can find all kinds of descriptions of how to "properly" wax and tune your skis. I offer up here an "improper" way to get that done, and it is more than good enough. The best part is, it is cheap. The bad part is, it does require some effort on your part. Should take about 15min or less.
Tools needed:
Procedure:

Your done. No fancy ski vice, tools, table, iron.... Please note - little to no mess. You will definately notice an improvement in performance from your skis. I am not talking about your speed down the run. Your skis will/should respond smoother/quicker/easier, your turns will take less effort to initiate, just crusing down the run will have a nicer feel.
A bit of scrounging around, and less than twenty dollars you can dramatically improve the performace of your gear and possibly get more enjoyment from skiiing. Ski shops charge about ten bucks to wax your skis and it is money well spent, but I cannot afford to spent money on waxing my skis very often. I do on occasion, and I appreciate the service.
How often does one need do this. That is up to you and your style. I wax my skis after 2 or 3 times skiing. Try it, I am sure you will like it.