Not sure about the resale value they could have since they are not common, but I don't see them selling for much. The only basic Kailh switch that people really buy is the Kailh black and that is mainly for parts since the stem can be used to make popular frankenswitches. Selling them for the 15+shipping you paid, is probably your best bet since for around 20 dollars there are better tactiles like the Gateron G pro browns, so it is hard for others to justify buying an older worse switch for more.