Well as I can see you already have websites there and those are worth a lot more than selling the single domain. For example, feelmobiles already has 1.6k backlinks and it's pretty old so you could get a couple of hundrends $, maybe even over $1k for it if you have some income. Don't know what to say about feelgps though. I would keep them and make my own blogs network with "feel" and maybe over years that would be worth thousands.