Some people have a strange idea of greedy.  I was told I was being greedy by one of the locals recently because I grabbed heaps of lemons off branches that he was about to take to the tip!    

I'd be really tempted to tell your buyer, sure, you'll halve the price - which half of the item would they like-  back, front, left, right?  

I've had a few people ask lately whether there are any discounts for buying more than one.  The first item was already marked down to two-thirds of my normal price.  I was polite and said no, and she ended up buying all I had (5).  The next one I blocked because I think it's just plain rude when I have nothing about offers or discounts in my store.  She wrote back and said "not sure why you've blocked me".  I didn't bother replying.  The latest one I just quoted the total price for what I had left and ignore her question on 'extra' discounts.

I had someone make me an offer (through a message) and when it hadn't sold a month later they offered again.  I think I ignored them the second time and was really glad when someone else bought it soon after.  If someone was as rude as your buyer I'd block them, but some will open a new account to get around the block.  They're not allowed to do it but it's hard to prove it was them.  Take note of the suburb that shows in the email where they ask a question and you'll have a fair idea whether it's them.