My first boat had old motor-scooter tyres with canvas covers sewn on. Very cheap to make (if you don't cost the time spent finding a source of old tyres and making the covers).
I can't remember anyone complaining about his boat being marked by them.
For anyone who is reluctant to buy 'proper' inflatable fenders.
One way of passing the time and of recycling old laid rope is to make 'pudding' fenders. Not difficult at all once you get the hang of it; in fact, it is also therapeutic.