Packt says that their ebooks are DRM free in the "Pactk Facts" section here: https://www.packtpub.com/about
Like other tech publishers, they frequently have discount codes on their ebooks, though $20 doesn't seem expensive if the information is useful.
They have very light DRM: they print your name (or whatever you give them as your name) in the book. There are no copy prevention measures, they're just straight pdf or other format.
It's actually a nice compromise.
Packt says that their ebooks are DRM free in the "Pactk Facts" section here: https://www.packtpub.com/about
Like other tech publishers, they frequently have discount codes on their ebooks, though $20 doesn't seem expensive if the information is useful.