Price. You can find lots of cheapo regulators for pennies each: http://www.aliexpress.com/7805-voltage-regulator_reviews.html http://www.aliexpress.com/7805-vo

Price. You can find lots of cheapo regulators for pennies each: http://www.aliexpress.com/7805-voltage-regulator_reviews.html http://www.aliexpress.com/7805-voltage-regulator_reviews.htm... However you usually get what you pay for so it's worth getting a genuine part.