Hmm, two cans of worms in one decision. I think I'd rather take advantage of ebay's own, er, framework, to avoid problems rather than put any terms in the listing itself. There's always that one buyer who overlooks them. Also this:
so maybe free shipping isn't a big deal anyway. Maybe if a buyer truly wants an item, paying shipping isn't really much of a hurdle. Sometimes I forget that not everyone thinks about purchases the same way I do (i.e. what is the absolute cheapest option possible, heh.) I think I can live with doing free shipping for any buyer - just not on every listing. I'll try using it only on what might be impulse buys.
Thanks for the help, guys!