Summary
Red wiggler worms are robust and suitable for indoor compost bins. If you do not have the finances to purchase them, you can find worms in compost heaps/in garden soil.
Type of resource
Store
Notes
Some mail order websites for red wiggler worms (search "Red Wiggler" to find others):
http://urbanwormwonders.com (Mission, BC)
http://worm-composting.ca (Chilliwack, BC)
https://www.burnabyredwigglers.com (Burnaby, BC)
https://wormworx.ca (Burnaby, BC)
Apparently 500 worms in a pound.
The worms are not cheap: over $40 for half a pound, but red wigglers do well in indoor compost bins.
The alternative is to collect small garden worms, from a compost or garden soil. Avoid the large ones.