I'm not trying to advertise, but purse.io does exactly what you want. Make a wishlist for the PS4, put it in purse.io and put the discount you want. Someone will buy it for you if they agree with the discount %.
Advertise? Do you run the site or are affiliated with it? How realistic is it that someone would fill the order for such a discount though?
I seen purse.io at coinsummit which I'll probably end up doing if I don't see anything by the end of next week. I just got a ps4 last week for myself at 15% off amazon price shipped to me in the US the guy was nice enough to even give 1 day shipping. I figure why not try and push it a bit and see if I can get one for 20% less.
I would be able to sell you $400 AGC for $340 worth of BTCs.
Send me a PM and we can discuss details if your willing to do $330 for it.