shipping extra or included?

if you are a buyer, does shipping make/break the deal? if you are seller, do you include shipping in price? i sold most of my speedo gears to include shipping. shipping was about $8. some things i sell, i ask for $5/10 to help defray shipping costs. most of my stuff has been acquired over the years. stuff i bought long ago, don't remember price. stuff recently acquired, might remember price. also, if using paypal for payment, do you always ask for 3-4%, so you get the full asking price. sometimes i do, on big ticket items. sometimes i don't. i, like almost everyone else is looking for a good deal, but that old shipping deal could be a killer. just curious.