As MaichBlack asked, why buy used tyres?
Used tyres are actually expensive.
I was shopping for Mark X tyres just a month ago.
Here are the figures:
Used tyres of 50% tread depth after haggling = 6,500 each.
New tyres (of 100% tread depth of course) = 11,000 each.
Now do the math.
To top it off, the new tyres seller gives a proper ETR cash sale and offers complimentary wheel balancing.
The used tyre seller would only offer a generic receipt and would just fit the bought tyres. Wheel balancing unajifanyia mwenyewe huko mbele!