The two bins I have now of red wigglers I actually stated by collecting them under logs, leaves, cardboard and whatever else got wet outside. Took about 9 months starting with maybe 200 to get large numbers but well worth it. They are really big and have been going strong for over 10 years. I think they have actually gotten bigger over time.

As for mealworms, last time I used them for bait I bought them from a local aquarium store. Were only $5 for 100 but that was many years ago.