Have two oxygen sensors for sale.
One was originally on the car when i bought it, replaced it as I thought it would cure my intermittent engine stalling when at idle and I wanted something reliable for my trip up to Scotland.
Replaced it with an NTK, but it made no difference. So works fine, can't remember the make though. £10 posted.

NTK O2 sensor, has only been used for less than 2000 miles before removing to fit a wideband sensor instead. £20 posted.