How about Shopify? Might be a little more expensive thought.
I think selling direct is a very tough area to conquer. Driving high converting traffic to your website is more than hard. In my opinion it's waste of time and money for most of us. All the buyers are already getting good and loyal service with micro/macro agencies. It's pretty hard to build a website that customers trust and buy from.
Something like Symbiostock could work, but it should drive it's traffic from Symbiostock search engine to really work.
If you want to get a lots of traffic to your website then you should give images for free. Only problem is that free traffic is so hard to monetize. Unsplash is a good example of high quality free stuff.
I have my own website with 3,000 monthly visitors and one sale for few dollars
I've let it be just a hobby as I can make so much more just by uploading to microstock.