the shops I worked at all had saddle bins though not out in the open, mostly we used them to swap back and forth for someone who didn't like the factory one and would use them on builds if people didn't state a preference. If the bin got too full then some would be put out though usually not the wider ones. The shop owners usually didn't care if one or two ended up on an employee's bike, just one less cheap item to inventory in january.
One shop I visit puts saddles out during their semi-annual sale and I tend to pick up a few 10.00 saddles for projects and helping friends. They also put out some drop bars on occasion so I do have some spare mid-level bars for whatever comes up. The last few months they've just had a pair of small square tables near the door with stuff they're trying to blow out. Another shop you have to ask if you want to have something and its whatever they come out with, screwed up a bunny hop over a log in the woods with the cross bike and they managed to surface a 26mm drop bar for 20.00 just for asking.