Woocommerce – any good? Any limitations?

I want to setup an ecommerce website
I was going to use Prestashop – but I want to stick to WordPress since that’s what I know best

Is it free, free? 🙂
i.e. not free – but you have to pay for a better more advanced version?

Just watching a video review on this now: they mention buying plugins for plugings – is that how they make their monies?

Off the shelf with little or no customisation: how good is it?

Thanks

Omar