Actually, I use nitrogen in the tires. No need to adjust tire pressure, and when you are on the highway, they don't change pressure. I don't pay for it, and don't know what people charge, but it is a good idea.. especially since most people don't ever check or adjust for temperature.

 

The site really is hilarious. I love the effort they put into their descriptions and the testimonials!

I didn't see where they sell ID-1OT lights though...

 

I have nitrogen put into my spare tires as well as my utility trailer, I dont use the trailer alot and there is nothing more frustrating that pulling it out from behind the garage and find out that your tires are flat.
Nitrogen will not leak out as fast, tires leak, they loose an average of 1-3 psi per month, that is why you need to check their pressure once a month and your spare tire once every 6 months.
Nitrogen leaks out at have the rate of air.
Some tire shops include it for free when you buy tires, other will "convert" you to it for a small charge.