At the risk of having everyone be mad at me.... 
No, really just some general comments, because I get some points made on both sides. I'm not trying to give anyone a lesson, because I know everyone here has plenty of knowledge when it comes to eBay and selling etc (clarifying that to avoid coming across as condescending, which is not the spirit of my post, it's just that the argument is going around in circles and from purely an observer's stance, it looks like some basic points are being neglected in favour of continuing to argue).
First, business, in its simplest form, usually means making a profit after all expenses are paid. If you make a profit by selling items to buyers, after all expenses are paid, then your buyer's payments are covering your expenses, no matter which way you break down the turnover. Unless there is another arm of the business where you are generating / depleting capital from another funding source. (I have no idea whether that applies to the business strategy of anyone here or not, so I'll just go ahead and assume nothing, though just to newdeals specifically, you did mention that your prices off-eBay could be lower due to the fees, so it kind of suggests you have accounted for them in your item prices, even if it's not a very specific or exacting process).
Two key business strategies are low profit - high turnover, and high profit - low turnover (that's not to suggest there isn't any business out there able to sustain low profit - low turnover, or high profit - high turnover, but the first two are more common, and profit is profit - whether or not a particular model is sutainable depends entirely on what the profit is supposed to be sustaining, which is different for everyone). The point is, one is not inherently better than the other, they each have their own pros and cons. I personally have two aspects to my business, one is lower profit, hight turnover, which is great for cash flow, the other is lower turnover, higher profit, and that's what helps me in other areas, like expansion.
Also, paying $20 per month for a store isn't automatically a waste of money for a low number of listings. It depends entirely on sales category and volume.
