Is this from a Craigs List listing or call?  Cars and pets are popular scam items on CL, and other buy/sell boards.  If you are looking for a specific breed of cat, you need to find a trusted source of breeders as a start.  Some of the Breed organizations are very active in finding homes for cats that are in shelters or foster care (an owner might move, or have died).

Almost all reliable breeders have the cat's best interest at heart.  In general, it is much better to meet the cat, but in the case of some breeds that might not be so easy. You would be surprised to know what breeds show up even in shelters, so don't exclude them shelters from your search.  You will know when you strike Gold - the cat will let you know.  A search for a breed can be fun, but keep an open heart!