1dollarscan tips

This isn't about how to optimize your 1dollarscan bill.  This about the things in 1dollarscan that I've used that worked and others that take some care.  I haven't used all of their options so YMMV.

1. As advertised, 1dollarscan does actually scan your book and does not give you a scan of somebody else's book.  So your own annotations and highlighting are preserved, for better or worse. 
2. Very occasionally, they do skip pages and it doesn't get caught in QA. I haven't ever had this happen with regular pulp paper books and trade paperbacks, but it has happened with academic books that are thicker and often have either thick binding glue (for durability) or very thin paper (because of book length).
3. Sometimes they do mis-cut books (i.e., cut off part of the content) and don't say anything about it.  Again, this is more likely with books with thick binding glue.  If you think there might be an issue, you might attach a note for the operator.
4. If you are scanning an expensive/hard-to-find book, buy the rescan option ($0.20/set). They'll happily work with you to address scan quality issues (e.g., light scans).  And if they do mess up and miss some pages, there is no other way to fix that problem. The fact that they only keep the scanned originals for two weeks is kind of a drag if you dump big boxes of books on them, though, since it means you don't have much time to check all of those scans for completeness and quality.
5. 600dpi scans are expensive ($3/set instead of $1/set) but useful for books with tiny print (like academic books).  However, it looks like 600dpi bilevel (b&w) scans are converted from 600dpi color scans, so if you have lots of free disk space and have the ability to reprocess the scans, it may be worth converting from color to bilevel yourself because you can probably do a better job than they can of filtering, thresholding (thresholding works better than dithering with scans that have more text/lines than patterns/halftones), and denoising the color images into bilevel images with clean text.  (I wish they would just do native bilevel scans, since in my experience a desktop scanner does a better job of producing a clean bilevel scan than an untuned software conversion from color.)  I say this from experience: the 600dpi bilevel scans I've received from them are noticeably worse than the bilevel images I've been able to produce from their 600dpi color scans.
6. Also, if you get color scans you can remove highlighting and correct other color problems in the process of converting to a bilevel image, whereas if you select bilevel or grayscale scans you're stuck with whatever artifacts were introduced by their color scan conversion process (which was not customized for your book).  (Note that for scans of black & white documents, ordering grayscale doesn't save you any disk space over ordering color - they're using JPEG compression on both anyway.)

(None of this should be construed as a complaint about the service - I use their service all the time and have given them more money than I want to admit.  The fact that they exist means that I don't have to keep a kid-unfriendly guillotine in my house, do continuous cleaning/maintenance on my desktop scanner, etc.)