Heavenly Sword - bought beacuse it was £4 in a bargain bin about 2 years ago, had a fantastic time playing it and ended up doing loads of research about the game and devs so I could follow them further. Really good.
Hyperdimension Neptunia Re;birth 1 - series gets constantly slated, and yet this was an incredibly solid JRPG that I could recommend to pretty much anyone.
Pikmin - was given to me for free with a used Gamecube I bought in 2007 for about £30. Ended up being mind-blowingly good.
Portal - I don't think anyone who played this at the time expected it to be as good as it was.
Summoner 2 - never played the first game; bought the second on offer and it ended up being one of my favourite games of the PS2 era. Incredibly solid western action-RPG with lots of Japanese flavour in there.
Wild ARMs 3 - the other half of the offer in which I also got Summoner 2. My first game in a series that eventually became one of my favourite gaming series of all time. Fantastically well-made JRPG with an epic, sweeping story and beautifull unique world.