I am going to make an online store, but i couldn't figure what more features are offered by paid softwares like X-cart which i can't find in free ones such as prestashop. from my view, they are pretty much like each other. thank you
There is no reason you cannot use free cart software - I use opencart myself, but what I did and recommend is you do a test install of the software you are interested in and really work with it for a bit - try it out by adding some products, customizing the look, going thru the work flow to process and complete orders, etc. You want to find something you are comfortable with using and that makes it easy for you to run your store, so give them a test drive before you decide
I used WooCommerce (with a couple of extra plug-ins), didn't spend a penny on it and still pretty satisfied. Turned out it's also not hard to use (my wife joined to help me in the business and learned to add/edit positions and similar store management stuff in literally few hours).