Surface Pro Pen Tip Set for $7

Pen Tip Kit is included with a purchase of Surface Pen, or you can buy it separately to have extra tips on hand.
Compatible with Surface Book, Surface Pro 4, Surface Pro 3, and Surface 3

$10 on amazon (even more from other sellers)
$7 here for you. No tax, no shipping extra! pickup on campus

https://www.amazon.com/Microsoft-RJ3-00001-Surface-Pen-Tip/dp/B01697GO4S/ref=sr_1_1?