They're worth it. I have so many pages bookmarked and things highlighted in my bought-new copy of SCSW that it looks like a used textbook on its 4th broke college student.
I swear I have to look something up at least bi-weekly
Also for the record, you might double check if it still stands, but when I bought it full price on Amazon it included a digital Kindle copy that I quick reference on my phone.
If you're anywhere near an Ollies, they have a good selection of gun books at their locations. It's where I get my annual Gun Trader's Guides --- $9.99 for a $29.99 book.