I don't think there's been any better value for me than Gary Bernhardt's Destroy All Software. I randomly stumbled upon it way back in 2014 when I had just learned my first programming language and was dabbling in Ruby, watched everything, and it made me much better at my job. It was $29/m at the time.
Apart from that, I think maybe one or two books every year. Most of them are pretty poor, but the value of that odd book that totally changes how you think about certain things is pretty high. A lot of technical books also have _really_ good, practical advice that can be applied to day-to-day work if you want to read them. It's pretty valuable to know the technologies you're working with in some depth.