I have put a load of stuff on the NZ equivalent of Ebay - called Trademe. I think it runs along similar lines to Ebay.
Anyway, usually, as soon as an item sells within 24 hours I have made contact with the buyer or seller (50/50 who contacts first in the past) and by day 4 the whole think is usually sorted.
Anyway, I sold a stair gate on Thursday for $70 (they go like hotcakes - put it on for $15 and it just went crazy).
Now, Sunday night I still haven't heard from the guy. I emailed him on Friday. I know he is pretty local and I offered to drop it round or somewhere near him. No reply.
How long do you normally give a buyer to reply to your emails?