Thank you for your opinions.

I understand your points and I realize that possible value of .net will be in most cases only just a small fraction of price it could have if it was .com

But anyway … in my opinion 55$ is very low.

Although I understand, that you can be right and those 55$ can really represent real commercial value of this domain.

But for me it is just too low to be worth selling it.

Instead of selling it I decided to keep this domain and to monetize it little bit with simple search engine project aimed at stock pictures.
(Project is online and running now but it is still in development.)