Hi jkzimm04, and welcome to SaleHoo,
Looking at your question from a marketing point of view, the business name you choose at this point isn't really going to be an issue, I would suggest just something general that you like if you are going to register one.
Of course you may have to trade on ebay under a completely different id, just dependent on what's available.
Branding will become important once you start trading of ebay, but a brand doesn't have to be built around a business name, it can be built around the products you sell, around a logo, or the image you want to portray to customers, and any business name can be incorporated into those branding methods.
If you did decide that you wanted to incorporate a business name better suited to your branding somewhere down the track, then you could look at a name change at that point.
Regarding which is the best option to start with, well I would suggest just starting with regular ebay listings, no need for a store unless you have the products to stock it.
There are cheaper alternatives than ebay, but none have the traffic that ebay does, and learning the business is about making sales, so ebay is the best platform for any new seller to start out on in my opinion.