FWIW, I have NEVER sold a cue for less than I paid for it, custom or production.
In pretty much every instance I have sold a cue, the person has seen me playing with a cue or I am playing a person and they have asked to try my cue. After trying it, they offered more than I paid for the cue. Sometimes, I turned down the offer and then they offered substantially more. Sometimes I sold and there are other cues that I kept no matter how high they offered.
I have been offered over 10 times what I paid for a couple cues and turned down the offer...one of them is a production cue.