First you need to figure out which game you are talking about.
Radiant Silvergun is a saturn only game that can easily go for $100+ on ebay.
Ikaruga is originally known as Radiant Silvergun 2 in development. $50 is about average price for the DC version. You can get the gamecube verison for a less.
Edit: I saw the "IKARUGA 2" on ebay that's basiclly the first Ikaruga.
What the above poster said. Ikaruga is the spiritual sequel to Radiant Silvergun. Radiant Silvergun is only available for the Saturn (unless you buy the arcade version). I don't think I would go above $50 for the Dreamcast version of Ikaruga.
If you find that Radiant Silvergun for $50, lemme know. It usually goes for $150 or so. I had it in my hands once at EB back in the day, but it was $70 at the time so I bought Dracula X instead.
[quote name='alongx']If you find that Radiant Silvergun for $50, lemme know. It usually goes for $150 or so. I had it in my hands once at EB back in the day, but it was $70 at the time so I bought Dracula X instead.[/QUOTE]
yes...if hell freezes over and i find 2 for $50, i'll let ya know