racketboy.com

I know the NCAA 2k3 GC was RARE, but I remember reading this somewhere like a few years back where someone had stated that this game was cheap and RARE at the same time.

Hm. Well, er... It's a sports game. For a Sega system no less. Few collectors go after that combination. Doesn't appear rare on Dreamcast, its PS2 cousin might be a bit scarce.

Virtua Tennis 4 on ps3 move Spring 2011

It is very common, about as far away from rare as it could be. Perhaps the ps2 version is slightly less common, but I doubt it.