The point of the $15 fire extinguisher is not that they are "inexpensive". The point is one should not have an empty extinguisher. Yes, there are many good quality commercial extinguishers on the market, but a person should buy what they can afford, and know how to use it.
I agree that the best option would be a rechargeable extinguisher and keeping it serviced, but the majority of the extinguisher owning population (commercial and individual) does not maintain and service their extinguishers in accordance with the recognized standards or the manufacturers recommendations. Yes, the extinguisher that came with the Deuce may look cool, but the thing probably hasn't been propery checked in twenty years!
Any extinguisher that is UL listed or FM approved will generally be a decent one, no matter where you buy it. I have heard of Chinese extinguishers without the UL or FM label. Stay away from those. Generally, a 2.5lb Dry-Chem ABC is good for passenger cars, light trucks, and your home. For medium and commercial trucks and your garage or basement workshop, I go with at least a 5lb Dry-Chem ABC. (The weight rating is the weight of the charge and not the total weight of the extinguisher)
Graingers for example sells good extinguishers at a reasonable price, or look in your local yellow pages for fire extinguisher companies, they're all over.
Keep in mind too, that the dry chemical powder is real corrosive to electrical, electronics, and some metals.