Commissions are negotiable and some fees may be discounted but that really depends on the Realtor you use and their relationship with the escrow, title, etc.. Other fees a seller has, HOA document and transfer and possibly a home warranty for the buyer, pest work if needed, repairs and things can't be negotiated and may vary depending on your home and the condition it is in.
Also be careful of those that promise a very low fee upfront or are eager to discount their fees/commissions so easily just to get your business, sometimes you truly get what you pay for. Also in my opinion the sale of your property is not an area you want to skimp. There are many facets of the sale that need to be properly handled. Also I always wonder if an agent is so eager to give up money, their commission, then how protective will they be with your money?
Good luck with your sale,
Brian Wilson, Realtor