Here's one currently at $99 on eBay that you don't see come around often and it has some great pictures worth archiving here. Also someone here might be interested.
The Comtronics AM-100 came out in 1997 and appear to be of solid construction. What's interesting is it's crystal control and set to 800kc (see radiomuseum link below) which is something the auction doesn't mention. Still seems to me a bargain price for a "like new" part 15 AM transmitter. Particularly to an antique radio collector.
https://www.ebay.com/itm/116781702808
Comtronics AM-100
Home/Hobby AM transmitter on a fixed 800kHz (crystal controlled) that complied with FCC part 15 at its time of manufacture. Has Line level and phono inputs. https://www.radiomuseum.org/r/comtronics_link_xmtr_am_100.html?language_id=2#google_vignette
The last picture I was looking for the crystal can, don't see where it would be.
I noticed it got some more bids.
Speaking of crystals, I was just wondering if any of the Talking House transmitters models ever used a crystal, or for that matter did any of the original Radio Reality transmitters they were based on ever use a crystal. I know the history behind the transmitters but don't know the first thing about the transmitters themselves!
Incidentally, in another of his auctions he has a beautiful radio, currently at $350 with one bid. I like antique radios, don't have any, and seriously doubt I would ever entain spending more than $50 on one, you have to admit this one is probably worth around $500 (not that I would know).
Jackson-Bell JUNIOR Refinished and Fully Restored - Playing Very Well
https://www.ebay.com/itm/116777415169
Love those tube radios. Some were beautiful pieces of furniture.
Like that transmitter too. Not good only operating at 800 though. Says meets part 15 and would be good if it was frequency agile.
@mark Well I don't know, it being crystal set 800 would probably make it inviting to a antique radio collector. Or.. presumably one could switch the crystal out with whatever frequency you wanted, but, presumably again, it probably doesn't have any circuitry in it to enable retuning.
I'm just speculating.