I don't know if a lot of people enjoy "making 
offers". (I find it SO hard to make offers, and 
usually with no success). It could possibly limit 
your quick sales.

 What works a lot is if you make a page with 
prices, post it here... wait until the buyers 
here diminish, then take the remaining to ebay 
and sell them there. 

hope that helps
~Tara