If you don't have Blackwell, the bundle is available the Bundle in a Box pay what you want bundle with a few other games.
http://bundle-in-a-box.com/
I heard of Blackwell but is it really worth it? The time, not the money. I doubt it could be any cheaper than this.
YES! Yes it is worth it. The first one is pretty average because it's one of Wadjet's early titles but as the series goes on the plots and especially the banter are done so well that I'd rate them above Gemini Rue and Resonance personally. Gemini and Resonance had sprinkles of humour but Blackwell is full of it, and yet it still manages to get very serious, tense and sad when the story requires it and it does all of these well, the pacing is terrific. You'll also notice the quality of the puzzles and UI steeply increasing as Wadjet get better at making adventure games with each one they release.