I have a process that I follow before and during selling.This is just my opinion.
1. When pricing your item don't look at what sellers listing price. Look for the "sold or complete" price on all websites to get your base price to list. Many sellers will list a ridiculous price and they think this is what the market pricing is.
2. Unless the price is firm; I will accept an offer with a 15% and 20% less. This is retail sales standard practice. Some sellers believe that 10% is a great discount, but in my opinion,10% is not an exciting offer to give for items under $500.