I agree that the RAM prices in the mp3car.com store are high. But you can only blame yourself for not doing copmparison shopping to insure you got a good deal on the RAM.
It sucks, but you learned a lesson.
Here's the listings for 512MB sticks of PC2700 RAM at Pricewatch: http://www.pricewatch.com/memory/4560-1.htm
You can get Micron-brand RAM (which is good quality and has a lifetime warranty) for half of what you're offering yours for.
Have you looked in the FAQ yet?
How about the Wiki?
Under normal circumstances, a signature would go here.