It is worth it IF - you have more than 25 images to put up - IF you are really serious about having an 'artist website' that looks professional - if you want to drive customers to your work.
You get an additional 5% accessory commission on sales. For me that has added up to $60 so far this pay period alone and there is still a week left to go in that fiscal month.
It is definitely a long term commitment finding success in a very competitive environment. It takes three years of work to establish any kind of presence in a business and most people give up after a few months.
The $30 is a tiny amount in the scheme of things, and is good value. Where the cost to you is time, a factor which does not get mentioned here often. You might spend weeks and weeks marketing your work, and sell nothing.
If you are only going to have 25 images then it probably isn't.
Why not try the free option to see how you upload ,describe and key word your images.
Also set all your defaults do your bio etc basicaly get yourseld all set up to go.
If after that you think you are going to upload more then pay for the upgrade.
That's what I did and $30 isn't too much a price to pay
It wasnt my first sale, but my last one paid the annual fee. It breaks down to $2.50/month. Where else can you put an unlimited number of pieces up for that price? Well worth it if you are going to be serious about selling.