http://storegadget.googlelabs.com/
http://googledocs.blogspot.com/2009/12/now-even-easier-use-google-docs.html
<<As you may recall, the Google Checkout store gadget, available in Google Labs, allows you to create an online store with inventory managed from a Google spreadsheet and payments accepted through Google Checkout. Today, using Google Docs and Checkout to sell online became easier with the introduction of a new store gadget wizard.>>

Not for the majority of people. Works only from US and UK.