Actual Hemp Rope

Not really magic, just a much needed and long overdue correction... Because no one bothered looking it up in ANY version of D&D, 100 feet of half inch thick twisted hemp rope (suitable for climbing on other dungeonesque duties) weighs three and a quarter pounds... and at best that much rope probably costs a silver piece.  PS - The same amount of silk rope of the same size would have cost something like 100gp or more, and weighed in at 2 and a half pounds, though it would be considerably stronger and tougher than the hemp, though also almost comically elastic.

So it's a third the weight for twice the rope and way less cost... you're welcome.

Notes: Utility, Exploration