First off, read Google’s description of its’ latest product:
Google Base is a place where you can easily submit all types of online and offline content that we’ll host and make searchable online. You can describe any item you post with attributes, which will help people find it when they search Google Base. In fact, based on the relevance of your items, they may also be included in the main Google search index and other Google products like Froogle, Google Base and Google Local.
I know Google said that the payment tool it came out with before was not to be developed as an eBay/PayPal killer but with the addition of Base – I can’t see that NOT happening.