I would suggest seeing if the US collector will cross the border with the game and you guys can do the trade on Canadian soil... and here's why.
1) Neither customs officials will give you a pass onthe value of your machine in the 'trade'. Your machine's perceived value will simply be treated as a cash value. So, if you're thinking of suggesting that you only pay tax on the cash portion of the deal, that likely won't fly. They will want to know the purchase value of the AC/DC and that is what you'd be taxed on.
2) In my experience, US buyers coming into Canada get almost no hassle when bringing a pin home. I have rarely heard of any US citizen getting dinged for taxes on purchased goods... especally goods of US origin. They seem to simply have different import/export policies on personal items than the Canandian side. For this reason, if you can get him to travel to (and cross) the border, you both should win.
3) If you bring a game into the US yourself, US officials will want to know why. If you state that you are planning to sell (or trade... makes no difference), you will be seen as doing business in their country without permission to do so. It wouldn't go well and I think anything above $2K in value will get further scrutiny.
4) Using a shipping company in either direction to cross the border is an expensive proposition. You will not only pay for transport, but you will also need to get a broker involved and they charge stupid fees for processing your goods through customs. As mentioned above, you can do this yourself for free or you can likely bypass it altogether if the other guy is willing to cross and meet you on this side of the border.
Lastly, I don't work for the government and what I've written above is purely based on my own anecdotal experience. Your mileage may certainly vary.
Good luck!
