ecommerce website

I want a website to buy products like the layout and functionality of buying a mac on apple.com. Not that big - only 4 products with a few different options on each (add/remove like the apple site). Nice and big, clear, easy to use. Would prefer to not to use an out of the box solution. Would like a coded site and add a credit card processor like stripe or paypal as I choose (not sure yet). Also want option to process the order without taking payment. Anyway, shouldn't be a big job for someone who knows what they are doing. Prefer FOSS solution. Thanks :)