I sold my KRC-3 over 10 years ago for $1300.00. I bought it new for a little less than $3000.00.
Well the first review in Audioreview was in December of 1996 and states a list price of $2950. Here is a link, you'll have to scroll back to the beginning manually. I don't know when it was discontinued, but I'm pretty sure it was NEVER $5500. The seller must be confusing the KRC-3 with some other Krell model, perhaps the KRC-2.
Looking at the reviews drying up in 2003, I would guess that is when the KRC-3 was discontinued.