Quad bike tyres as cheap as possible

[mat777]

Hi everyone,

Our gliding club has a golf buggy used to tow gliders across a grass airfield and it is forever getting stuck when things are wet. It runs 18x8.50x8 turf tyres on it, but it has been suggested we scrounge some old knobby/chevron tyres to put on the back of it.
Does anyone have a set to fit it? It could probably go from 7.50 to 9.50 in width and from 16 to 19 inches in diameter. We are a quite impoverished club so if anyone has a used pair too worn down for mudding, in the back of the shed they are willing to donate for free/ under a fiver we would be extremely grateful