Note about free samples.
This all depends on what exactly it is you are requesting for, but mostly applies to semi conductors and the like.
The free samples that you receive are (usually, but not always) chips that did not meat the manufactures specs. There is nothing Wrong with the chip per-say, but something caused it to be rejected. It may be something as small as a pin being 0.0001mm out of alignment or the marking might be slightly smudged. These "rejects" are often given away as "Free Samples" or otherwise thrown out.
As far as the manufacture loosing money, not to worry - they would have to give away a hundred times more than they sell to loose money. Once the master plate is made, they can run thousands a day for pennies. This is the same reason that the latest CPU is > $2000.00 when first manufactured and a year later you can buy it for $89.00 from Tiger direct. Once the R&D and initial run is paid for, the rest is 98% pure profit.
So if you only need 1 or 2, go for that free sample. It actually cost Mouser or Digikey more in processing your $2.00 order than its worth. If the manufacture don't offer free samples, call them. Tell them you are a student or hobbyist, most places will be glad to send you 1 or 2 as long as you pay shipping.