I buy sports socks in bulk from Sports Direct. Usually Nike or Slazenger, the 'half cushion' style with the towelling effect underneath. You can have just black or assorted colours and they last well and are really comfy. I'm walking around all day at work in Para boots and the sports socks and my feet are in perfect condition. You have to change them every day for the best use as they soak up the old foot-sweat but they're not dear. I've had some for years. They also do brilliant trainer socks. Don't buy running socks though as they are too padded and your shoes won't fit.