I have had a ‘hidden’ page available for a while where users can enter multiple ISBNs and look up approximate pricing for all of the books on one screen. That page is available at http://bookscouter.com/multi.php and available for anybody to use. It works similarly to the Paperback Swap Lookup that I posted about recently. The pricing displayed is from the last time the book was looked up on the site, and it provides a link for you to refresh with the current prices.
I’m posting this here in hopes of gathering some feedback about how it works, and how you think it might be done better. As usual, feel free to comment here, or send me a message if you have any comments or suggestions.