Blue LEDs cost considerably more than red, orange or yellow.
In quantities of a million or more, blue LEDs cost anywhere from $0.50 to $0.80 apiece, while red ones can often be found for $0.05 or even less.
When you buy in small quantities, you can get raped even more severely: the "going" price for red LEDs can vary from $0.20 to $1.00 apiece, while blue LEDs can cost anywhere from $3.00 to $8.00 apiece depending on type and where purchased.
As for having to "adjust" driver circuitry or other electronics, this problem should be very minimal and in most cases, converting a device from red LEDs to blue LEDs entails nothing more than changing a five cent resistor. Many devices (such as cellular telephones) require no modifications at all to make the change.
http://ledmuseum.home.att.net
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