Before the end of the auction a maximum price should be set and not raised thereafter. As most bids are placed only in the final minutes, it may be sensible to disclose one's own willingness to pay likewise only shortly before the close.
Cause for scepticism is the frequently encountered wording that the seller has been unable to test the function of the fountain pen, ballpoint pen or pencil because he does not know how the instrument works. As a rule such writing instruments are defective, for example because the piston mechanism no longer works. Here only a specific enquiry to the seller helps, or it is better to pass over the offer.