On a security note, there are several ways to lift text from even a protected PDF file, regardless of the security settings embedded in it. For one, a screenshot of the open file can be processed with any number of OCR (Optical Character Recognition) programs to produce an editable text file.
While it is more of a bother than copying-and-pasting, the truly motivated thief (or a person who is legally using the material under "fair use" regulations) can get at your content without too much trouble.
The same can be said of "meatspace" books, I should note. A scanner and some OCR can do the same thing to works published in even that elderly technology.
If it turns out that you really want to implement roadblocks to easy use of your text (and I don't suggest restricting the print function, as I, among others, do not care to read books on my computer screen), then you can expect to pay the full price.
If you decide "what the heck", and just want to e-publish the darn thing and trust your purchasers' discretion, there are several free PDF output programs available for download, among them the excellent PDFCreator