Depending on where you're at in CO, Denver has a few nice restaurant supply stores that are open to the public. You could consider the plastic containers that you'd get soup in takeout from a restaurant. They come in several sizes, and they're relatively inexpensive and you wouldn't have problems with bags possibly breaking.

I've used feed sacks, burlap bags, cardboard apple boxes, and sandbags. The sandbags are available at hardware stores for a reasonable price, and they porous and breathe, and hold about 5 gallons. I've not used labels.

I bag them in brown paper bags like you get at a 7/11 when you buy a six pack of beer. I have lots of those bags on hand.

Chuckiebtoo

Sandbags may be available inexpensive at military surplus or at a "Cheaper than Dirt" catalog I have heard about.

To fill the bags with sand or vermicompost put an orange traffic cone up side down in a hole in a piece of plywood. One person shovels into the cone. A second person holds the bag under the cone and seals up the bag.

Worms are sometimes sold in bags made of material similar to those $1 reuseable grocery bags but thinner. Perhaps it would work for vermicastings also.

I do not recall ever reading a post on this topic before.

canvas bags are available at banksupplies.com.

If you are bagging VC in freezer bags, your customers are buying dead vermicompost....which is just somewhat of a fertilizer....at best, and nothing more.

All that you see sitting vacuum-packaged on the shelves of "organic" retailers gathering dust is also dead, and not at all what the customer is paying for. Every time I see that stuff on the shelves I make a note to cross that producer/distributor/retailer off my lists.

Chuckiebtoo

BTW:

A great container to keep your "curing" worm food in for a few days after thawing, if you freeze it, or cutting up if fresh before presenting to the worms. If previously frozen, be sure to drain all the moisture out of it first.

Thank you all so much for your excellent suggestions. I am checking out some canvas bag samples now and I'll try to post a pic of my finished product when it gets done. Thanks again and happy wiggling!! :)

I use the rather large white, woven plastic(?) feed sacks (used for oats) for storing my vermicompost. It can still "breathe" but retains the moisture well because of the material it's made from. Probably too big for selling your stuff though.

You may want to check out the bags used for rice. We eat a lot of basmati rice and much of it is sold in burlap bags or some kind of breathable material and often have a zipper. They hold about 5 lbs. of rice, so might be a suitable size for what you need.