I generally tell the truth because its too easy to forget what you told to whom and its much more embarrassing if I get caught on an untruth. That includes SA's, yes I tell them, I got your brand on Ebay and all the good ones don't mind because I also buy from them as well, in fact, if the bag is interesting, they've actually asked me to wear it in so they can look at it too - usually discontinued bags that are rare.
If anyone looks down on you because you bought a used bag, they will do so regardless of what you do, you can bet they will go and find something about you to knock you down. Trying to appease, get along, or simply be accepted based on lying/fibbing/hiding the truth about a mere handbag will ultimately lead you to repeat the act over and over until you lose your own self-respect with nothing gained. And good people no matter who they are, what they do, how much they make or own will be happy for you all the time.
As for pre-loved bags, like you said, often times people buy them because the style got discontinued by the time you found out about it and you are simply playing catch up. Quality of leather and craftsmanship has gotten worse compared to a decade ago, even with premier designers and so people choose to buy used/vintage and pay top dollar. By why explain that to people who are not nice to begin with? Also, the way that you tell them probably will make a difference. If you said you looked high and low for a particular color and tell them why its the one you HAD to have and say it like you mean it, people will be too scared to disagree with you, lol.
