The kits are fine. They are neat to buy. I would think most of them are fine in quality and results. But you dont need them. Here is all you need.
Go to the grocery store and get Parafin Wax. It is clear and is made for canning and skis and snowboards. Its the same wax in those kits by chemical standards. True the kits may containe waxes for different temps...If your a pro on the jeep tour...fine. If your like me an idiot on the hill

Then just get the regular parrafin wax and you will be just fine.
Then u will need a scraper..Many stores now have large ones I see alot. U do need one of those.
Ohhh yea..I forgot those cheap green scrubbies u get at the dollar store...Get the multi pack. Its only a buck. U need those for polishing
An iron...key for sure. Get an old standard iron from someone or just get a new one. If u take care of it and melt the wax properly it should last for years. I have had mine for five years and I regulary wax my boards with it. It is a standard household one. Dont get the mini ones because they cover less surface on the board when spreading the wax.
One way of keeping an iron in good shape is when your done waxing the board, unplug it and hold the iron level in the air, rotate it forward and backward as the wax drips and burns off. Let cool for about 10 minutes or until it is warm, then put it on a glass hot plate holder with a paper towl and the wax excess wax will absorb into the paper towl. I turn the towl over a few times.
Again the kits are fun and fine but they are not mandatory.