I purchased my worm bin for about $65 after taking a neighborhood class LA County hosted. It came with the worms and coconut coir, which is the bedding for the worms. There are also plenty of options online. My worm bin looks just like this but I don't use the legs as I have it on my gardening table, and I only use two trays instead of three - I may advance to three trays later on. Once you get it started with fruits and veggie scraps and some shredded wet newspaper you can leave it alone for a week or so at a time as long as it doesn't dry out. Make sure to keep it in a shady spot.
This is a great option for those with limited space or who don't have a sunny spot for a compost bin. It is also a great option for parents or teachers who want to share the nutrient cycle with kids.
LA County Worm and Compost Bins