I'd have to 3rd the wordpress suggestion, if you had a big site with lots of pages and a involved user portal then Drupal would be the goto suggestion. But if it's a smaller site, no need to deal with the issues of a huge site if you don't need to.
Joomla isn't bad, and can be managed but unless you're a webdev you'll want access to info and scripts and by far the most popular choice is wordpress.
Just make sure you do a thorough product audit so you can reduce the overall amount of product before you put them online, this will help SEO drastically, since you'll have less pages that users would draw attention to that don't work too well.