Squarespace shines at design and usability, and their ecommerce offering doesn't disappoint. You get a standard store complete with coupons, variable sizes, physical and digital products and flexible shipping. Sales taxes are only available for the US and Canada right now.
Pricing starts at $26 / month which is not prohibitive.
Conclusion: Squarespace gives you a beautiful looking store, well-suited if you want to start selling just a few products right away. You'll probably not be happy with it if you have tons of products and need many custom features.