Keep an eye on their twitter, pragprog occasionally has coupons, usually on holidays. Manning always had coupons and deals.
Both pragprog and Manning blew past O’Reilly in terms of quality of content years ago. In both cases you’re paying for non-DRM’d media: mobi, pdf, epub. O’Reily’s Safari service is okay, but last I checked you’re stuck reading online (not bad, but not ideal), or using their reader app (not great). Huge selection though, and I think some manning, pragprog, and no starch books are included.
If the book is good, ebook or physical, I generally won’t blink at $30.