Gotta look at your overall costs. A) check to see if the final value fees are going to be different. Items sold in the store are straight across 7.5%, but includes shipping. B) listing fees - if you stay within your first 50 listings for free each month with auction style, then you'll pay more. If you normally list them as a "buy it now" only, you'll save as the listings are only 5 cents each. C) the minimum store price is $15, so you have to look into the costs vs the savings.
Some nice things, you can have a listing for 30 days. If the item doesn't sell, it automatically relists itself. You can add a "best offer" option, which can be hilarious sometimes as some people will offer you 10% of what your BIN price is. Thankfully you can set amounts to decline below and amounts above to accept. With a store, and offering free shipping, your listing is brought up higher in the "relevancy" search.
There is more organizing available. Instead of just all of your listings in order of price or time, you can categorize them to make it easier for buyers to search for ones they want.
Even with a store, if you do an auction style listing, all the original rules still apply. Like listing fees, final value fees, and such. There's no special discount given.
One thing that does help, is to have a "tag" in your photo. Like either a specific background, an emblem, or something that can be recognized as buyers scroll through listings. If they start to see your "tag", they're more likely to check out all of your items for sale or contact you to see if you have a specific pin available.
