Lovely to see foxy being suggested.
Except they don't offer a free plan (which as a designer, it's something I'm interested).
All I want, is to build a website and add some products to showcase before transferring it to the client and let him subscribe for the other features and add the other products.
And that's where ecwid.com is useful.
You get up to 10 free products and with a bit of CSS knowledge, you can customise everything.
You simply add the code (store, category or even a single product... They supply the code for any part you want to place on the website) and you're ready to preview how it looks! You'll have to publish the page to view the code tho...