you need to buy red worms or ones specifically for this use, the ones in the fishing section of walmart wont do the trick, ( so ive read ) i could be wrong. but since your feeding your worms basically food scraps, it has potential to mimic the environment of a compost bin, and at our house we compost or food and even if we keep the bin inside it swarms with gnats, so i would keep the worm bin outside because its possible that the same may happen. but still worth it if you have space, and time. it doesnt add up over night, ideally you need a few pounds of worms to, but building a bin and buing enough worms can be done with 25 dollars or less. you can order the worms by the pound online or get them at a feed or garden supply store