This was the last trophy I got. By the time I finished everything else, I had 75 deaths. To blast through the last 25 I loaded up the Labs and found the green goo fire for quick deaths. When the stats load you can press Square to Restart and repeat until done.
The part to remember is if you are going for other trophies and fail the objective, rather than Restarting you should kill yourself. Otherwise you will have a longer trip to get to this one.
I have added a tactic on my solution for getting the buy all powerups trophy. The end of the tactic is to kill yourself, so it may make sense to combine these two trophies: