According to a product engineer that I talked to a number of years back most companies like TI, Analog Devices, Motorola (back them) were happy to send a few parts out to anyone who made even a small attempt to look 'official' as it helps with company image to a great extent as a lot if not most were people who were in a position to influence ordering. The other thing he said to me was that "We make 10K of those devices in a production run and we lose more to testing and imperfect processing and accidents than we could ever sample, the real issue he said was/is the cost of handling and shipping freebies. He further said that if there were any accounting done on the parts they woulld be a small write off for tax purposes as advertising. The thing they would prefer not to see happen is things like the Analog Devices AD9850-1 thing years ago where people were requesting 2 or 3 of the things 2 or 3 times. If you make even a small attempt to look for real they usually will co operate, the only thing you might find is a salesman with too much time on his hands. Their calls can be an annoyance. It was the 'Product Engineer' who told me how to do the whole thing just as it was described by the other guy contributing to this thread topic. He pointed out to me that it was nothing to give away a $20.00 (Retail..) part when your annual sales is about 20 million parts a year total.
So, people were sampling those to build their roll-your-own function generators back in the day and abusing it? They seem quite inexpensive, now at least:http://www.ebay.ca/itm/NEW-AD9850-DDS-signal-generator-module-0-40MHz-/170682095715?pt=BI_Signal_Sources&hash=item27bd721863#ht_4213wt_905
The part Analog sent me (ADS58B18) was significantly more expensive than that. But I only asked for one and will not be asking for additional ones most likely.
My thought was that shipping was the most expensive thing too. The expense in the part is the R&D which they are not going to retire a penny by not sending out a sample. The incremental cost of making the parts is almost nothing when the expense of one part is considered. Now the shipping, these guys all sent my samples FedEx 1 and 2 day without even asking. I would have been happy with USPS and they would have saved a bunch of money. And they send the parts in the largest most professional shipping containers imaginable, for a speck of a part.