I've been selling on Ebay about 2 years now but still learning. I started with just listing without a store until my inventory got more or until I got a hang of the basics. I always list with Auctiva saves me money since I like to display lots of photo for my buyers. There are 3 levels of a Ebay Store: Basic, Premium, and Anchor.
I opened a Basic store which is $15.95 CDN a month which allows me 5 pages. If you are new I would go with listing without the Store until you get a hang of things. GOOD Luck!