I would check with Jan Crystals.
http://www.jancrystals.com/index.htmlLast time I did business with them, they were making something called an HC-17.
It is an HC-6 size crystal (same spacing as FT-243), with thicker legs on it,
so that it will plug into an FT-243 socket. They were selling for much less than you just quoted... think it was $15-25 each plus shipping at the time.
What you should know is, whatever frequency you order may end up off by a couple kHz + or - when you plug it into whatever transmitter you are using... and, they take a number of weeks to deliver.
They also sold me some of the leg adapters, which I soldered onto some of my own HC-6 crystals to make them fit FT-243 sockets.
You could also change one of the crystal sockets into a socket for HC-6 sizes, on your transmitter.
Or, dismantle an unwanted FT-243, and wire an HC-6 socket onto the top. I made one of those... ugly, but it works.
These folks have some surplus HC-6 crystals within the pirate range, and they also sell the HC-6 sockets somewheres:
http://www.surplussales.com/Crystals/Crystals-3.htmlThey always shipped incredibly fast, too.