We used to have a compost pile on the farm was no problem the red worms were all over the place so if you're in a place where you can start a compost pile they will be there.
when I was a teenager I sold my crawlers for a penny apiece was a good way for me to make a little pocket change to buy more tackle the problem is I couldn't keep up with the demand from the sporting good stores on a good evening in most of the parks where I lived was no problem picking up 500 or more in the evening my uncle bought a deer rifle by picking up nightcrawlers I don't know how many thousand it took to buy that rifle I know was one hell of a lot of them.