I'd just go to about any store anywhere and buy a thing of night crawlers. All the convenience stores, Walmart, etc. have them for fishermen and they're pretty cheap.
Garden newbie question: did you add worms just for the poop? Do people usually add worms to their garden soil or did you do this because you're using a bucket?
I'm a complete newb also. I added them to keep pooping but I'm going to have to also feed them some basic stuff and I can't fertilize this soil now that they're all in there. So that's why I'm glad that the one plant is dead because that will now become where I burry a banana peel or some other easily compostable scraps for the worm's feeding needs
But don't trust them, they're also slippery little dudes.