You won't be able to buy a new 1080p 3D passive display now. You can always check craigslist and pawn shops for one. 1080p passive will halve the vertical resolution. All new 3D TV capable displays are 4K. The cheapest passive is the 55" LG for 1300.00 with HDR.
With 4K you'll be able to see full 1080p per eye though. I just saw on Amazon they still had last year's model OLED 55" for 1800, but it was before HDR feature was added, new models are 2800.00 for 55".
Depends on what you want to spend. I wouldn't buy a used one without checking model number and seeing the specs and how old it is first. Compare prices to new first and see if it's a good deal.
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