Block pulls are a fave of mine, and I will be using them in a cycle leading up to the meet in April in conjunction with pulls from the floor.
This past weekend I went to Home Depot to grab what I needed to pull from blocks. I prefer pulling from blocks rather than the rack because it feels more similar to floor deadlifts. In a rack the bar is bent and some of the inertia is taken out of the bar because of that. So there's really two reasons to pull from blocks rather than the rack.
I picked up the shit in this video from Home Depot for around $55 all told. I had them cut it at the store to save myself the trouble of fucking with it when I got home.