1 On average, be prepared to spend $10 to $26 for every 50 feet of ethernet cable. 2  For instance, this 14-foot AmazonBasics cable retails for $5 to $7. 3  A spool of ethernet cables that has to be cut and crimped yourself will cost aroud $75 to $200 per roll. There are many unbranded ethernet cables available which may be cheaper, but they may not be as reliable and could malfunction after a few months or years. 2  On average, be prepared to spend $10 to $26 for every 50 feet of ethernet cable. 3  For instance, this 14-foot AmazonBasics cable retails for $5 to $7.