"I have a GBA cartridge that contains Phantasy Star 1, 2 and 3."
Me too, picked it up in France for 10 euros (about £6). Also picked up, while I was there - Lemmings for PS2, Final Fantasy IV, Bust-A-Move DS and Castlevania: Dawn of Sorrow. All of these were £6 each too, brand new.
I didn't really enjoy Phantasy Star though, but I guess I was comparing it to Final Fantasy.