Need Advice - Online Surveys or Other Work at Home Schemes??

I have signed up with probably over 20 paid survey sites, even some of those well talked about ones, and still cannot figure out how you actually make money on them. Some people seem to be successful with them, but it seems to me there's always some catch as far as signing up for ';free'; offers, and not so free offers. I just want to be sent regular surveys, and surveys only to my email without having to try to work around all these stupid offers. Can anyone offer me any advice? I am a stay at home mom with a spouse in the military all in need of a little extra income if possible. Or any other work at home ideas that do not require a large investment are also welcomed. Thank you!!