I just use regular stamp pages which I make up myself. The standard printer-friendly size here in Australia is A4, acid-free paper is a must & I use generic ink, I'm not going to be around in 100 years to see if my ink has faded.
For cheapy postcards I use whatever corner mounts I can find but for any decent covers/cards only use
Transparol made by HERMA, they are the best, no argument. Prices vary a bit, a quick google shows this to be a good price, I'm sure there are other sources.
http://www.ebay.com/itm/HERMA-TRANS...130897691385 I use 3 mounts per item, both bottom & top left, this way the stamp area, top right, is clear. This makes it easier to remove the cover if needed & 3 mounts hold the item very securely
If there's anything on the reverse I want to show I scan it, trim it if it's just a postmark (Irfanview is an easy free proggy that will do this), put a border around it, then bring it into my Desktop Publisher, which in my case is the free version of Serif Page Plus
Here's an example of one of my pages
