Usually only the most recent issues are available as back-issues. $6.00 USD each includes shipping in North America. The best attempt is made to print enough to supply all immediate demands so there are a number of copies available for months after the issues print date. It is difficult to gauge. Back-issues are listed as available on the main page and removed as they sell out. Reprints are made from time to time. Advertised reprints have color covers and plates like originals.
Older issues that are no longer available as back issues or reprints can be requested but may require a few weeks for printing and upfront payment is a necessity. Reprints on demand are $8.00 USD each including shipping.