Depending upon the state and store you salary may vary from $5 to $10 normally for working in stores or any restaurant like Macdonaldz, KFC, Burger King, Hardees, Taco Bell etc. If you work as full time employee then you will most probably get health insurance however if working part time then mostly no health insurance.
If you are working as a full time employee which normally is a 9 hour shift in USA from 9:00am – 6:00pm or an 8 hour shift from 9:00am to 5:00pm but for restaurants of stores like Wal-mart, Target, Sears, JC penny etc then your timings will depends upon your shift which can vary depending upon the hours. Sometimes these stores and restaurants open from 6:00am till 12:00am midnight or sometime overnight as well.
If you are working 8 hours shift for 5 days a week you will earn $320/week and $1280/month. This salary is taxable; the tax will be minimum because the salary will be below poverty limit however still there will be certain tax that will be applied to your salary like medicare tax etc depending upon in which state you work.
If you are planning to marry a woman who is American national to have a better life in USA then you must know that such smaller scale jobs cannot be found easily because anyone can do it so American citizens or permanent residents get priority and then it’s your number.
So if you are not well qualified and thinking that after coming to USA you can pluck the dollars on trees then well, you are wrong. It’s not as easy as it seems especially with family this salary can’t fulfill even your basic needs in proper manner. In such situations spouses are pushed to work which can be done if you do not have any kid. If you have kid then daycares are too expensive and can cost you for about $500 – $1000 per month. If your kids are school going then yes your spouse can work till the time kids are at school