On Tuesday, August 15, 2017 at 10:57:41 PM UTC-7, wrote:
.... To some, $10K for an extra set of wingtips is almost incomprehensible when you can buy a glider for less than that.

....
Chip Bearden

Or since one usually buys the extra tips when they order the glider, the thought process is more likely, wow I can fly two classes for only an extra 4-5% increase in initial cost. And for the small increase in purchase price lowers you unit costs of 15/18 meter glider by half