Start lower- the bidding will raise the price and ebay charges less of a fee. People will bid what they're willing in the end regardless- you could get a storm of free attention (and lower fees) by starting at $1. who wouldn't jump in? Maybe not at $1, but still...
as much as i want a copy of KS i most certianly wouldnt pay that much for it now a year or so ago i would of jumped at the chance but as chris says with dosbox now there really is no need to pay that much