Hi Laura,
We have just produced an e-commerce site for one of our clients using Magento. You will need knowledge of programming for certain aspects of it and it can be tricky in places but it is very good.
If you are looking for non e-commerce, then we have also used Drupal which has done a great job for us and our clients like using it to content manage sites themselves.
Again, with these things, it takes a bit of know-how to set them up but after that, they are pretty intuitive to use.
Feel free to PM me if you would like to outsource any web development work. We would be glad to help you.
Regards
Dave