There are some decent vintage examples that pop up on eBay for less than $600. It is fairly difficult to find one that is in perfect playing condition though. Presuming that pads, springs, corks, and felts are all present and in good condition, you should still expect to pay about $150 to have the horn set up professionally by a tech. In the hands of a decent player, a good vintage horn can keep up with all modern professional offerings. In this forum there are differences of opinion as to which are the better horns. Here is a list of common less expensive vintage horns that are generally well favored by players. I did not include stencils as that would make a very large and less comprehensive list.
-New Wonder series II (Chu-Berry)
-Transitional (Many different designs, but all share traits between the Chu and 10M)
It is important to remember that there were low and high pitched offerings of these models. Low pitched horns are designed to tune to A=440. High pitched were designed for the European standard of tuning, which was slightly higher than ours. I think that high pitched Conn's are A=457 and are untunable to our standards. Make sure that you get a horn that has an "L" or "LP" stamped somewhere around the serial number. There should also be a "Bb" or "T" to indicate Bb Tenor saxophone. There was a C-melody tenor that was keyed in C and will have a "C" stamped near the serial number.
-400 (Any design in which the low Bb and B toneholes are placed on the back of the horn "facing the player" are prefered.)
The same rules that apply to Conn vintage horns above also apply to Buescher.
There are some older models that some players like, but the horns simply labled "The Martin" seem to be the most favored.
You will find some gorgeous King's from the early 20's that tend to be very inexpensive. These horns tend to look better than they play. Most players agree that the Zephyr is the horn that put King on the map. There were several models of the horn. The older Zephyr's with fancier lacqered or plated keys are pro models. The newer Zephyr's with nickle plated keys (these generally have a more mass produced look) are considered good intermediate models.
All of these offerings will feel very different from a modern horn. It pays to do your homework and play as many of these as possible to find out which suits you the best. If you can find any of these horns in good condition for $500 or less, pounce on them. If it turns out that it is not the horn for you, you can probably get all or more of your money back through resale.
Here is a "The Martin" currently selling on eBay.http://cgi.ebay.com/The-Martin-Tenor-Sax-Saxophone_W0QQitemZ290168662727QQihZ019QQcategoryZ16234QQssPageNameZWDVWQQrdZ1QQcmdZViewItem