I had a full ecommerce site running through the summer (it didn't work out) however I built it in Woocommerce.
Its all very simple and works very well.
It's not a fully blown custom system, so you do find yourself working around things a little - but for the money you won't get anything as simple or as well sorted as that. Highly recommended.
If you know Wordpress then you shouldnt have any issues, if you do have trouble there are loads of support forums etc out there.