I'm wanting to connect my PC to a radio to monitor one particular
frequency.

The instructions I've been given say to use a "scanner" but I'm
wondering if it maybe less expensive for me to go with a "receiver" set
to the proper frequency. Since I'm really only interested in the one
setting, I don't see why I'd need a scanner - unless the price of a
scanner is about the same as a receiver.

Now if a receiver will work for me, what kind should I be looking for
and how do I adjust it to get the frequency I want? I'm assuming I have
to install a specific crystal or something. But since I have no idea
what I'm doing, I may be way off base. I hope the people here who are
knowledeable can help me learn what I need to in order to do this.

The other issue that may be a factor: the instructions I'm following
talk about how scanners have a "discriminator" on the ear jack that is
where you make the connection to the PC.

"Scanners" generally work only above 25 or 30Mhz, up to perhaps 995 MHz, with
some "holes" in coverage.
Although there are some that are crystal controlled, a programmable scanner is
just as cheap.

But you don't define the frequency, the distance from you, the modulation mode.
All of these are needed to give even the beginning of a satisfactory answer.