Most expensive game for me was a Motorstorm Apocalypse Press Kit.
Some gouger offered it me for £200+£30 shipping.
Normally, I would have declined, but even after waiting for shipping, it meant I would get the game 2 weeks before its official release date (It arrived 4th March, and official release was 18th, until it was delayed in respect of the Japanese Tsunami disaster)
Also, I had just sold a Gran Turismo 100 million edition that was signed by the series creator Kazunori Yamuachi for £260. So to me, it was like easy come, easy go.
Interestingly, my cheapest game was actually the Resistance 3 Survivor edition. The one with the hip flask, toy soldiers etc?
Gamestation screwed up my payment some how, so I got it for free
And still to this day, I have not had any emails, messages, letters or any sort of notification from the bank. Result!