theres a bunch of variables to consider in selling.....
but you could always start around 1500.00....
but to catch most eyes, and a rather faster sell, venture on to most stuff would be around half of what you paid.....
and most times you only factor into advertising a price as what they cost brand new or on sale, which was ever lower, even if you didn't get the sale price....most people shop around and know....
you don't include tax, delivery, or warranty....unless you plan on delivering/install, and providing a warranty for these machines...
check what others in your area are selling a similar set for.....whether from an owner or used dealer....