I need some guidance....

I work with a girl who, she and her boyfriend, have just had a garage sale this past weekend. Her boyfriend has a lot of really really old vintage items. Apart from old guns, and swords and cabinets, books dated in the 1920's, etc.... and he has a lot of ephemera.

Knowing I'm interested in things like that, she brought in the vintage ephemera and I'm drooling over it!! A lot of it is dated in the 1920's. Some post marked post cards, greeting cards, old score cards from board games, etc. She plans on putting the remaining items on "craigslist", so I mentioned to her, "Let me know what you are asking before you post that."

This girl I work with..... she is.... "that girl" that every office has, that is sort of quirky and easily "miffed" and often makes a "tense" office atmosphere.

She keeps insinuating that at the garage sale this past weekend, no one wants to pay and keeps trying to bargain with her and she has let things go for way too cheap. This followed by, "how much would i say something like this goes for?" I told her I've never bought anything like that before, and I'm really not sure. (The sticker from the family garage sale is still on each of the zip lock baggies, with $1.00 marked on them, each bag containing between 5 and 20 items). She says she thinks they meant $1.00 per piece of paper.

I by NO means want to rip her off, but I also know her personality and the constant "victim" role that she plays. I want to be fair with her but I don't want to be taken advantage of either.

Can anyone give me a guideline or some sort of base as to what vintage ephemera goes for?