In article t,
Ralph Mowery wrote:

Digikey has for sale crystal oscillators that can be programmed for most
any frequency for around 2 to 3 dollars. I have even ordered them
already programmed for about $ 4 each. I am sure in quanties of
thousnads from the manufactor they are very inexpensive.

I have ordered those for a project.
Certainly cheaper than having crystals made for $18-20 each.

$ 10 to 20 is inexpensive for a special made crystal now. I only know
of 2 places right now, Bomar that last report was $ 50 per crystal and
minimum of $ 100 for an order. Another in England that is I think about
$ 30 per crystal.

Those programmable-frequency oscillators may have distinctly worse
phase-noise characteristics than a real crystal in a good oscillator
circuit. They may not necessarily be suitable for communications
projects or others that are sensitive to phase noise / jitter.