I have been looking for a local source for composting worms. I don't need many as I'm starting a small undersink vermicomposter. If you could spare a few handfuls of worms or know where to get some around Missoula I'd appreciate a lead. Thanks in advance!

Howdy Jessica, You might call your local Master Gardeners, via your county extension office. They might know of someone who would help you get started.
And welcome to permies!

You can try collecting wild ones and see how they do in your vermicomposting setup. Don't get the big night crawlers, they need it too cool but the small/medium sized ones that come up when it rains might do the trick for you. Look on pavement after it rains or put down some damp hay and collect under it a few times. You can even buy some at the fish bait places, they were grown in someone else's vermicomposting, after all! I think "trout worms" are the same thing as red wigglers usually.

jessica-

I'd check with Garden City Garden Supply at 525 E Spruce. Last I knew, they had some.

If you really aren't in a hurry to get the compost and can't find somebody local to share, you could just get a tub of redworms at your favorite bait store.
This isn't how I would suggest most people start however 30 can turn into a lot in a year.

My partner and I vermacompost and are always willing to barter.

I saw a think on Craigslist. Don't remember exactly what it said but I bet if you searched for worms it would come up.

Just look for someone with a manure pile they will be redwiglers and there's usualy lots of them.