Cheap yet outstanding probably won't happen.  Recognize that a used horn will generally need tech service (no matter what the ad claims state).  When buying a used sax, I would expect that it might need $100 to $200 minimum service.  If the pads are shot, the minimum can quickly jump to $500.  So you should really have enough budget available to handle this contingency.

I cannot tell from the photos exactly what model Kohlert you are looking at.  Here is a link to a Kohlert sound clip from the Saxquest sight.  

https://www.saxquest.com/product/view/excellent-condition-kohlert-soprano-saxophone-serial-t00467-P11615 

Again, I cannot tell if it is the same model, but it is close to the same age.  This horn sounds nice, but note the price, and the fact that it is not in a fully serviced condition. 

If you had a lot of cash, and wanted to take a gamble on this horn...why not?  But it sounds like that may not be your case.  I would recommend saving up some more money, and then buying a reasonably priced horn from a reputable dealer as the best way to protect your investment.

Good luck!