Is Amazon's 'webstore' any good?

I'm at the very early stages of setting up an on-line business. I'm publishing children's books, printing t-shirts and associated items. I've never had an on-line store before.

I was looking at the Amazon webstore product. $60 month. I thought the idea that the shopping cart was seen to be an Amazon product would indeed give credibility as the Amazon sales pitch suggests.

So, anyone know much about this product? Does it compare well, price wise, with alternatives? Pros and cons?

Also, I was wondering how many Gigs are needed for a store to operate well. When looking for a company to host a site they give options, but this means nothing to me. I would expect my store to have a little flash going on, and such, and just want to make sure that I wouldn't have problems with the site being too large for the capacity the host was providing.

All advice welcome on these subjects on anything else that comes to mind.

Thanks a lot in advance.
Simon.