There's a simplest system for beginning racers (basically using all temperature wax all the time - the cheaper one for training and more expensive for racing). There's no point spending large amounts of money, time and effort on this before the technique warrants it.
If you progress past the simplest system and want to "get into it", move to a regular 3-tier system described below: training, racing and overlays.
All temperature waxes are great here. We are racers, so we stay with the cheap low-fluorinated.
One of the simple-to-use waxes that I like is the Hertel Super Hot Sauce - normal paraffin with surfactants - easy to put on and it feels like a fluoro. It's also good to -15 C or so. Under -15 C, I switch to some harder stuff like Kuu's green or Swix bulk cold temperature (blue). Hertel sells a "cold snap" hardener, but it's a damn pain to use.
Other good stuff to consider here would be RaceWax's all temperature fluoros. Should you use non-fluoros? Sure - they're cheap and easy to work with, so see how you like them. The idea is to provide a consistent glide, so pay attention to conditions: on a wet day, use the High Fluoros.
One way to look at this is to use racing grade for training as well, maybe depending on how well they do this season and how far from race day they are. At the beginning of the season, it's all cheap stuff - late in the season when there's like two races a week, it's all racing grade for training as well, to keep the skis behaving consistently.
Another way to look at this is to consider that in a training day, the wax looses most of its effect / is gone in a few runs, so might as well use any appropriate wax - this is a good approach!
For race day, it's time to get the more expensive stuff. Here's the theory: in the lower leagues, kids do not race for 5 minutes, but may, in fact, ski the entire day and race in the afternoon - so you want something decently fast to last for the day.
This is the medium-expensive fluorinated variety in each system - everyone has a "middle tier". You apply this hot, so it lasts for the day.
Why fluorinated wax? Well, we ski on a microscopic layer of water and fluor hates water, so it helps to float on the thing, i.e. makes the skis faster. The more Fluor, the better. It is the modern-day equivalent of pitch and tar:
Pine tar glides on snow because it’s insoluble in water. Water beads on it nicely, forming droplets instead of sheets. This means that at a microscopic level, the ski glides not on a sheet of water, nor on hard-point snow crystals, but on the equivalent of tiny liquid ball bearings, mixed with a lot of air. That’s good because air is about 99 percent less viscous, and therefore a lot faster, than water. Seth Masia, GRIP AND GLIDE: A SHORT HISTORY OF SKI WAX
Most systems get temperature-specific as you get to the more expensive stuff. Exceptions are Hertel and Nanox - both have only all temperature super-fluorinated for racing.
I have used the Hertel FC racing for 2 seasons and like it - not too hard to put on and stays there for the entire day. I do wonder if the other stuff is faster or different, so this season I will test it against the RaceWax selection and the Nanox system (if I can bring myself to spend 200$ on that stuff).
Update: no, they're not better on wet snow! However, both Nanox and RaceWax waxes are more consistent across many snow conditions. Also quite a bit more expensive! So here's the conclusion about these three:
There would be a reason to use only this all season long, for both training and racing - for the racers in the family... the skis get so saturated with the same kind of wax, it ends up lasting more and more. With the Hertel system, their FC racing variety has special additives that make it more flexible, so again - a good reason to use only this for the racing skis... the drawback being marginally higher costs for a season and having to use a respirator all the time (you should use a respirator for Fluoros).
The most expensive are the overlays, the last layer that goes on the ski. Every system has this super super stuff, at around the same price. I used Hertel's all temperature for two seasons and was good - theirs is a hard wax. I tried RaceWax's mid/ high-end stuff and probably Nanox's. The difference they make depends with snow conditions rather, like dry new snow - where Nanox feels better and the molybdenum additives (in RaceWax's top line) start to make a difference.
If your kids race FIS or higher, then you know what I mean and probably use it exclusively. This is priced around 100$ per ounce (25g) and instead of melting it, you use the touch and rub method. It may only last through the first race of the day, although there's less skiing on race day, so you're hoping it lasts for both races unless you have two pairs of skis with you - which is normal at the FIS level.
Since we're here, there's one last thing you can easily do for your little racer. At the starting hut, I sometimes use some super-fluorinated paste or liquid - these are stinking fast but wear off in a few gates as well - it does make for a smoking start, especially if the first section is flat.
Do not forget the fact that, beyond a simple waxing job with a decent wax for the conditions, the expensive race stuff is only of marginal importance for race results, especially in the tech events.
However, for certain conditions, special formulations can make a big difference, especially in dry snow conditions (where your skis don't want to glide), where moly/graphite or other such additives are very important.
Read on for even more Ski Tuning Ideas.
Here is the a selection guide for much more details than I care to know... right now.
Hi, my daughter has been using Javelin Diamond wax now for 4 years and she loves it, but really doesn't know anything else... http://javelinsport.com/shop/javelin-diamond/ I was sold on it when I emailed the "Inventor" and he called me back the next day, and we talked for around an hour.
I have never found out what is in it for floro content, so we do go through allot of BP88. Also when we put the Javelin wax on, we Rub, light Iron, then rub again so 25 Grams, will do around 6 to 8 pairs of skis. It does go on a bit colder at 125 C.
Have you tried there wax? do you have any comments? Our Coach, Dan Hadley, tried it, and he seamed impressed and told us if my daughter believes in it, best to stay with it.
I tested a lot of waxes, but not this one - thank you for the link. Sounds much like the Nanox, although that one is all-temp while this has 3 temperature ranges, with a total of something like 5 different snow conditions (the "black ice" sounds more intriguing - that's a tough snow to wax for).
It is not cheap though, by any means, but it would be worth a try, when compared to the others.