Hey guys, first post here. I'm planning to buy an iMac soon, and I've been checking out eBay for possible deals. I found a guy who has a late 2013 27" iMac with a 3.4GHz i5 processor, 8GB RAM, and GeForce GTX775M 2GB graphics card (the exact model I want). Now, apple has this exact computer refurbished on their site for around $1650. The eBay listing is for $1795, but has the "Make Offer" option to haggle. My question is, what's a good price to offer this guy without being insulting? I'd want to pay at least a little less than Apple's price, but I don't want to make him angry and ignore me. Any tips?