Apple peripherals, like all of Apple's products, don't come cheap. It's why it's a good idea to hang onto the cables that come with the product's original purchase, as most of Apple's connectors cost at least $19 to replace.
Apple's Thunderbolt cables, first introduced in 2011 to connect to external peripherals, used to run for $49. The hefty price is matched by its hefty length of 2.0m.
Thankfully, the company's seen fit to slash the prices and the length on its Thunderbolt connectors. Now, a 2.0m Thunderbolt cable costs $39, and the more compact version, sitting at 0.5m is an almost reasonable $29.