Never ever buy used tyres unless you see them removed from a brand new vehicle right infront of you. My past experience was very bad. 5 Years ago, I trusted a tyre wala whom I knew for years, and took a set of 4 used tyres and installed in my Corolla 98. That tyres looked fresh with zero punctures. Right after 2 weeks, one tyre busted just at the speed of 70kmph, resulting in climbing a footpath and hitting a pole in such a angle that the left side centre pillar hit that pole and car was squeezed from middle. Both front seats joint together. Thanks god nobody was sitting on left side. It took around 1 Lac to repair.
So what I learned from this is that 2 things should never be compromised at all,
1st is the tyres and
2nd is the breaks.
I would suggest you to buy cheapest Brand New tyres but never go for any branded used tyres.