Since Ebays fees are SO high do you think a store is the best route to go if listing 150 items a week? Are stores all BUY IT NOWS or can you do AUCTION style also?
It really depends on what you plan on selling. How often you plan on selling. And if, after listing 150 items, you can make a profit. Most of the comic stores on eBay are just retailers selling excess inventory or just making extra sales online. If you have a lot of stuff to sell each week then probably a store would be ok. But if you just be selling things randomly or at various times, then you wouldn't need a store.
Depending on what you sell its better to do 30 day listings with BINs and Best Offers functions. Auctions are becoming the gutter of ebay and all types of headaches arise from doing them IMO.
i can't see why anyone would use auctions over a store setting and if you are listing 150 things a week it would benefit you greatly from reduced fees and time saved from relisting.
The usually advised minimum to have a Store is 50-55 unique items. At 150 a week, 600 a month (?) you are well over than minimum.
Advantages are reduced fees, automatic relisting (if you choose Good Til Cancelled), the ability to sort by category , and no worries about when to have your listings end. And you set the price.
Disadvantages are no Fifty Free Auctions, not knowing who your customer is until he buys (thus, no cancelling unwanted bidders), and occasionally finding something sells so fast you KNOW it was underpriced.
If you are just relisting the same 150 over and over, then a Store save a lot of work. If you are have many more than 150 books, then the more you have in your Store, the more sales you can make.
You can have auctions in a Store, but the concept works best with Fixed Price/ Good Til Cancelled.