In my Worm Factory the burlap cover lasts maybe 4-5 months before decomposing into shreds. That's with moving it to new trays as I swap them out about once a month, give or take. Once the burlap is too bedraggled to serve as a cover, I incorporate it into the tray material and it breaks down completely within a couple more months. I guess the Worm Cafe is basically the same design as a Worm Factory but results may vary depending on moisture and warmth and so on. Burlap is handy stuff to have around so if you are getting it really cheap I wouldn't hesitate to stockpile some, you may find it gets used other ways too.

With only 1000 worms it will last a while , but after a period of time it will be used up and need to be replaced.

What's the sale price?

I read here a couple of months ago that coffee roasters will often give away or sell cheaply used burlap bags. I asked at mine, and they're a dollar.

I cut one sack in half and folded it over to make a four-layer cover. Two months later I see very little decomposition.

I live in Europe, not in US. Burlap was found on sale at IKEA, 4 meters for 2 USD. It's not announced by IKEA, I wasn't able to find any information about it anywhere, and I'm not sure if it's possible to find it in other IKEA stores or not, but the product is called BRÖSTBÄR. I wrote a message to IKEA asking if it's safe to use it for vermicomposting and they told me that it's safe.