Here are some sites where you can buy Manic Street Preachers CDs, posters, DVDs, books, T-shirts, etc. I have personally dealt with each of these, so I know they're trustworthy.
Note - there is no video from Richey's last show! What is sometimes labeled Richey's last show, is actually from the show on the 20th, the night before. There is an audio recording of 21 December, (Richey's last show), however. You can hear or download it from this site. Go to the "Sounds" page.