ORIGINAL: bigedmustafa
Glow plugs contain small amounts of platinum in the filament that is necessary for glow combustion to take place. A rise in glow plug prices was inevitable due to significant price increases in the precious metals markets. Platinum has gone up almost 80% in the last eighteen months.
The good news is that platinum has dropped significantly within the last 60 days or so. I doubt we'll be seeing a corresponding drop in glow plug prices however.
Take a look in your local "items wanted" ads. You will see several asking for your old catalytic converters. Platnum is the item in your catalytic converter they want to recycle/sell. For some reason the platnum gets hot and glows when exposed to hydrocarbons (I'm sure ther is more to it than that, but...). Thus "cleaning your exhaust emisions or ignighting your glow fuel as the case may be.