It might depend on where you live too.
In Minnesota the buyers pay most of the closing costs (unless they negotiate differently).
The average buyer who is using FHA (3.5% down) or Conventional (5-10% down) will probably have about 3 - 3.5% of the sale price in closing costs. This covers loan origination, title work, appraisal, fees, taxes and setting up initial escrows.
The average seller will probably only have about 1% of the sale price in closing costs in the form of state deed tax, title fee and a few other minor charges. Obviously, their commission would be on top of that but you can certainly find less than 6% too (I charge 5.5% and provide full service - so they are out there).
I'm sure a local real estate person can give you specifics for your market.