Last Strada I bought was five bucks. You can ignore this price safely, however, I find 'em cheap; the real value is certainly higher. Exage is kinda lower end shimano. Below Dura-ace, RX100, 600, Ultegra, 105, and probably a few more. Good, nothing amazing. Tange did make some very nice tubesets-- I had a Panasonic made with Tange "1" tubing, that was a beautiful bike. They also made some straight guage stuff. The Strada I have is straight guage. I really don't know enough about the Bianchi models, but the Strada I've got is Taiwan made.

Personally, I think 189 is a bit high for what I think is an entry level road bike (at least the one in my basement is). However, is the bike in good running condition? New cables and housing? Chain? All these things can up the value, along with where you live, as bikes seem to have wild geographic fluctuations in pricing. In NYC or Cali, it might be reasonable; here it isn't, I don't think. Keep in mind I am no Bianchi expert nor have I seen the bike.