Wix is one of the most popular generic website builders, which means it's not specifically made for artists, but it's also flexible enough to showcase and sell your art. It has a forever free plan and several paid tiers that you can switch between with ease as your needs increase.
It has some artist-y templates but whichever one you end up choosing make sure you don't stick with the custom pictures, because lots of other websites out there will be showing them also. With you being an artist it will be a breeze to fill your website with unique pictures that set you apart and make your website unique.
Wix also has a great app store that you can use to customize your website according to your particular needs. Some apps are paid but some are totally free, like the "Wix Art Store" app that helps you sell your art online with ease.
You'll probably want to use your own domain name which will cost you $4.50 and will also increase your bandwidth to 1Gb