Taken to buying second hand off forum recently for tyres, £100 notes for 4x CDX alloys with 6mm Kumo 31's fitted. Done about 3k on them, wearing very well.
Dunlop Winter Sport 3Ds with 6mm tread for a bit more cash, mounted on CD alloys.
I know its no good now, but worth keeping an eye out for breakers in future.
Thought quite seriously about that approach.. and decided against it ... reasons actually quite simple ..
I spend a fair amount of mileage towing 1600 Kgs of van, often for 4-5 hours at a time, which is a fair amount of stress on the rear tyres. On other occasions I sit at around 85 for trips of 11 hours with just a few 30 minute stops ... again .. high tyre stress situations. Ok .. rest of the time is pootling about at 50-70 for up to an hour or so.... but it all adds up to around 12-14000 a year.
Part worns, of any make/type/description/provenance are unknowns .. have they been kerbed ?? potholed ?? overinflated/underinflated ?? I just don't know ... and all such things
can lead to internal failures .. which
could bite me badly if it all went pete tong.
With new, I know the history, what I've done to the tyres and where they've been (rightly or wrongly) and so have a degree of knowlege on which I can assess any risk.
At the end of the day, we rely on four very small patches of rubber to keep us on the road, for the sake of saving a few pounds, I've decided the risk is just not worth it ... to me .. but it might be to someone else... as you have decided ..