So since I last commented on the subject, Godzilla's stepped up his game a bit: I've been able to find both the 1954 Godzilla...
...and the 1998 Godzilla, which my sister and I have currently dubbed "Unpopular Godzilla."
Gamera's still in the lead, though, because it's hard to top releasing all one's movies but one for about ten bucks. The only way that the turtle could step up that game is paying me to buy the last movie.
On the other hand, there's supposed to be a complete DVD release of Godzilla: The Series, and if I ever find that, Godzilla's score will go way up, because as I've said, that cartoon blew the movie it was tied into out of the water in every respect. (There's even a long-standing rumor that the cartoon's version of Godzilla was given more respect by Toho than the movie's, though there's not a bit of truth to it as far as I can tell.)