I personally have been the victim of overpriced technical certifications. I found this blog to be very telling.
Enterprise Architecture: From Incite comes Insight...: The Economics of Industry Certifications
It seemed like there was some sort of scam going on to charge me $150 to take an online test (regardless of the outcome). As it appeared prometric was the only provider, I figured it was a case of single supplier economics. It appears that is the case.
Anyone interested in putting certification tests online for a reasonable price and fostering a community of certified professionals (and not line the pockets of a monopoly provider) should setup an assessment with a certificate on DigitalChalk.