In fact, there were two bindings - spiral binding and perfect binding. The spiral binding was by far the favorite, which totally makes sense; being able to do puzzles without having to fight with the binding is the better experience.
However, in the interests of seeing where this project might go, there's an opportunity to get an ISBN, which opens the doors for all sorts of additional attention - Google Book Search only cares about books with ISBNs, and many of your popular bookstores (click or brick) have a similar requirement.
I had been planning to save the proceeds of the book until I could afford the ISBN price strictly from the book income, but I got impatient, so I funded it out of "real" money. It's not a lot, and I've spent more money in the past month on game controllers.
I went through the process to update my book with the ISBN, and I'm finding the Lulu.com layout cumbersome. A friend just mentioned a new website, http://www.createspace.com/ which I might check out for my word sudoku book.
The thing I meant to talk about when I started this post is that now that I'm reaching further into the retail chain, there are more steps between me and the consumer, which means more mouths to feed, which means a higher price. In the abstract, I'm OK with that - I'm getting a wider audience without a lot more work on my part, and presumably some of these avenues will keep a few on a shelf, so you can get a copy without waiting a week (the horrors!). However, the retail price seems a lot higher than I would have expected - adding more than 60% over the print-on-demand price.
The good news, though, is that the spiral binding is unacceptable to the ISBN process (?!), so the higher price only applies to the perfect-bound version of the book. So, fans of the spiral bound edition will still be able to get copies of it that way at the same price as ever. Also, the downloadable version seems like it's working (finally), so if you wanted a version that didn't kill trees, that's an avenue that's open.
I will, of course, provide a link to Amazon if and when I get listed there.