Whereas your basic assertion is correct, many simple components that cost $0.18 in quantity cost $1.50 each in handfuls. Shipping and its associated delay is also a consideration, particularly in places like where the O/P lives.

If he's on an extremely tight budget, exploiting the refuse pile is a serious consideration. Back in the day, I recommended junk piles as a resource for students who couldn't for one reason or another, find, or afford, some of the components they needed. Most of the time, TTL is undamaged even after years on the refuse pile. MOS components ... Well, all bets are off, but my own experience, limited, to be sure, with desoldering parts from junk boards, and in my experience the were rejects, so something was surely "broken" has been quite surprising. I also recall reclaiming memory IC's back in the '80's, from boards rejected from outgoing inspection, when they those memories were scarce, from boards with nearly 300 of the things, socketed, thank God, and finding only 2 or 3 defective memories from among a half-dozen boards. The problems causing the boards to be rejected were apparently with the TTL bus-interface devices rather than the memories.

It's no less likely that the professional will receive defective IC's from a distributor than a "scrounger" will receive them from a surplus lot, unless those surplus boards were inspection rejects, in which case they're usually tagged as such. Keep in mind that a board with 1000 components will be rejected if there's one defective IC or even passive. It often depends on which refuse pile was the source.

If the O/P believes it warranted, he can build a "functional tester" to verify that he has a counter, register, buffer, or whatever, if he's willing to develop his own set of vectors by means of which to verify them. I see no reason to discourage him. I would, however, discourage him from attempting to use the libararies for the old 1980's SuperPro, simply because (a) he doesn't have one, and (b) if he did, he'd find they weren't that valuable. Parts that were really important required that one write one's own test vectors.

RE