When mail art moves into history it must move into art history, or networking history, both are museum quality issues. If we mail artists are to be counted in historical importance, then we must agree to be counted in cash value. The past is a value position dictated by the market and by the people coming after us. If you are involved in a current exchange of mail art, then money will confuse your creative powers. Dont think about money as an issue in networked art, think about the future, about ideas, create new transmedia or traditional or evolving products, methods, art forms... But if you have a mail art archive that is worthy of preservation, selling the archive is a respected method of providing a safe and respectful haven for your collection in a research institution or museum or library environment.
This is my advice to mail artists with a legacy of an archive and the experience as a practioner: Please negotiate, not only the price, higher higher - the higher the price the more value that art historians will value the network, but also negotiate for your position as expert consultant for the understanding of the meanings that are rich within each and every piece of mail! Mail artists are the ONLY experts on mail art.