I sympathise with you - same problem. I researched this to the enth degree after I lost my second pair, and I can assure you of a couple of things:
If you buy expensive sunnies like Mako or Maui or Spotters or whatever, you are wasting you hard earned because you are only getting the frames, the lens is replaced.
If you want a graduated multifocal in polorised, get prepared for a long look and a big shock.
You will not get the above under $400, anywhere! If you can let me know! usual price around $450 to $575 or so.
I have looked at overseas and all options I can think of but getting MULTIFOCAL and POLORISING together means $$$$$$. Bifocals a little cheaper.