What ways do these companies cheat?Do they pay on time?Is it legal for someone in a dependent visa to do these jobs?

Most of them want to you purchase some "kit" that will allow you to do some job that there is no demand for in the workplace.

There is a good site for work at home moms that gives good advice and pointers.
WAHM.com The Online Magazine for Work at Home Moms

Sorry, no clue on the visa question.

If your visa doesn't give you the right to work it is illegal to take these jobs.

But be careful, a lot of these can and are pyramid schemes, they use complicated calculations to hide the fact that you have to get enough orders or you have to pay money to them yourself to make up your low sales.

Also and company wanting you to buy a "sales kit" is most likely a scam.