Keeping on topic, as a "backyarder" I find it really difficult to sell games as I worry about things going wrong - sure, a sale is a sale and without an explicit warranty I have no responsibility provided it was not misrepresented. But it bothers me if something does go wrong early on.
Personally, I would assist with phone/email queries for any reasonable period for general stuff (depending on the buyers expertise), and perhaps if local offer some help if a fault develops within a week or so (but probably not much longer particularly as it will probably have the sh!t played out of it in that first week if a newbie). Where to draw the line can be hard, but at some point you need to roll out the "I think you need someone with expertise now" and refer them to someone who can professionally help.
