PSP Promotional Disks

hi, are the psp promo disks worth much or are tey rare??
i just got a megaman maverick hunter x promo disk off ebay for $30 aud.
http://cgi.ebay.com.au/PSP-Mega-Man-...QQcmdZViewItem

there were also sfa3 and namco battle museum, but i didnt get those.

http://cgi.ebay.com.au/PSP-Street-Fi...QQcmdZViewItem

http://cgi.ebay.com.au/PSP-Namco-Mus...QQcmdZViewItem

I believe that promotional copies of games only really become valuable if the game itself ends up being canceled prior to official release. Also, if the game is recalled and edited for certain material, then the promo copy woulf gain value for being the original game data. Otherwise, promo copies just exist as uncommon variations of common games and don't really accumulate value.

o, ok, thanks for the info :)