For what it's worth.

[bbcard1]

I think there are a few factors, but I agree that honesty is the best policy. I have had the opportunity to fleece folks before, but it is not in my DNA.

1) Is it something you are actively seeking, eager to buy and would put in your collection without any intent to resell? In this relatively rare case, I would be willing to pay as much as 90% of what I would expect to pay after scouring ebay, shows, Net 54, etc. If you are lucky, there will one or two cards in the collection like this. Why not? You were looking for them anyway and you get a little discount over what you would have paid.

2) Is it something your would like to have and is desirable to keep and could be immediately liquidated at or near retail. I would probably pay 65-75% of retail. Exceptionally high grade cards fall into this category.

3) Is if ok stuff, like 1950s stars and commons mix that is sellable, but has to be discounted? 35-50% is plenty.

4) the dregs…the stuff you really don't want and are hard to sell, I would figure at 25% or retail or less. You should get it at a price where at worst you can stick it on Net54, get an immediate sell, and make 20% off of any day of the week.

It's sounds complicated the the final percentage really depends on desirably and need and if you are reasonably familiar with the hobby isn't that difficult to figure out.