PageRank of destination page
Probably no more or no less then regular search results. I wouldn't go chasing PR for this or any other reason. There are much better ways to improve a page's/product's rankings.
how product pricing affects placement
This only comes into play when a user chooses to sort results by price
how age of page affects placement
Irrelevant. Age of a page has absolutely nothing to do with the relevance of a product for search results. If it did new products wouldn't be found for who knows how long and thus the latest cool gadgets wouldn't be reflected accurately in the SERPs.
This is more useful to the user then to the search results. If the product image confirms to the user that you have what they are looking for they are more likely to click on your link.