most of them tend to be get 10 people to sign up and you get your fee back, then anymore you sign up after that you get paid for... any that you have to pay a fee up front i would avoid!!!
but saying that, they are a few legit working from home people around. My aunt used to do a few bits and bobs - building complicated gift boxes, that kind of thing. but she found the person who used to organise it messed her around with money. Her kids used to help and get a bt of pocket money for it!!