I am a JD guy but if I was looking for a cheaper sickle mower conditioner I would look at a NH 488. They have made that same model for over 25 years. Make sure the conditioning rolls are in good shape. With a good sickle and guards you can mow a lot of hay with them.
I would steer away from the older JD sickles mowers, 1209/1219 or 1207/1217. At this age they are getting to have issues with the sickle gear case. They are expensive to repair. The NH has a simpler drive system. It is easier to work on and the parts are cheaper. Plus if it is a major part you can find used ones.