When it comes to the cost of Apple charging cables, there are a few factors that come into play. The first is the type of cable being produced. Apple currently offers three types of charging cables - Lightning, USB-C, and MagSafe - each of which has a different manufacturing cost. The second factor is the length of the cable. Apple offers 1 meter and 2 meter versions of each type of cable, with the longer option costing slightly more to produce. Finally, there are quantity discounts that apply to orders of large quantities of cables.
Taking all of these factors into account, we can estimate that it costs Apple between $2 and $4 to produce a single charging cable. This puts the retail price of Apple's cables at a significant markup, but not an unreasonable one given the high quality materials and construction used in their production.