I do not know much about the 66 and 99, but the 221 and the 222 are the same machine but the 222 has a freearm and therefore is more expensive for the ones I have seen. I got a 221 off of ebay for approx. $250 Cdn and 222's are usually at least double that and I have seen them for up to $1000 Cdn (a little overpriced in my opinion).