Quick question, your help is much appreciated.

What do you all do when trying to sell a pink that has no others up for sale to base price off of? This happens more often than not with the pinks I get, and I just keep hoarding them because I have no clue what to ask for! One of them, the Lingering Death of Brutality (lvl 15) I've been lugging around for days continuously checking to see if others go up but with no success. I don't even know where to begin in terms of making up an amount.

Any tips? Thanks!