I am not sure if you had a look at the Amazon page, but out of these four lines, one is the main product ($269.00) and the other three appear half way down the Amazon page, in "Most popular" tab of product listing - you can easily match product description with what is shown in the snippet.
One of our sites has the same kind of snipped if "More shopping sites" is selected. From what we can see, it appears that if the search term is considered transactional and(/or?) the site is ecom site, and on the page that is ranking for that search term Google "recognises" list of products with prices, then Google will scrap four products and prices from the page and will list them instead of snippet.
We also saw that Google will take random products from the page (e.g. not the first few in order, or first few cheapest,etc) so the only control over prices and products shown in this kind of snippet is in terms of what you put on the listing page that ranks (as any of products on the page can appear as one of 4 product lines shown). Another thought is to reduce listing page to only four products you want to show in snippet (but perhaps then risking fall in ranking for that term if products are removed from listing - we have not tried this).
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I have also seen where there are more products on page, that there is fifth line appearing with the + sign and text
"+ 11 more items from $39 to $82" If you click on + sign, it expands and shows all products found on the page. I cannot see this on Amazon page, but can see on one of our listings pages which is shown in SERPs
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[edited by: aakk9999 at 2:08 am (utc) on Aug 1, 2010]
