This is a tricky one. I've ordered free parts from Digi-key, but they are not a manufacturer, they are a distributor, so they carry lots of things from many companies and they make their money selling these parts.
I first worked my way into their system ordering free samples for some Microchip CPUs that weren't available through Microchip at the time. I built a rapport with one of the account specialists there and was able to order several other parts for free for a digital audio mixer project I was working on. One part was a $50 high-end analog fader. I've gotten over $100 worth of free parts from Digi-key, and they shipped for free too.
