I assume you mean a hardware emulator, and not a software simulator (several free ones were/are available).
You want to look for HC11EVS (eBay or similar). Every so often something comes up.
I sold a few of them over the past few months and my last one earlier today! (Bummer.)
There was also a more expensive (and probably much harder to find) MMDS11.
Also, check out 3rd companies like Nohau, Ashling, and tec-i.
