if the sales are going to be big, as in maybe a few thousand a year, then try a big branded shopping cart, but you will pay.
foxycart sounds good as well, but you pay a monthly fee, regardless.
paypal only take a small percent of the sale plus £0.20 (check your country amount). I worked it out to be for a £20 product I would get £19.30 of that sale.
either way you have to pay for the privilige somewhere, paypal, is the best for the small trader