Food is pretty cheap. Focus on cheap and filling things like beans and rice as a base for meals. Absolute cheapest can be $80 a month with a price range at $.50 a meal or so.
Housing at least in socal for a 1 room apartment in any sort of decent neighborhood prepare to pay over $700 a month
Entertainment can be cheaper. Tv doesnt need any service, if you have one an xbox + friends netflix account is all you need. A computer if you have one only costs electricty, id advise not paying for internet and leeching it off a computer illiterate nextdoor in an apartment situation. This has risks so keep it in mind. Electricty cost for entertainment $20 - 50 a month. Other upkeep can go down to 0. In reality though if you have any sort of social life the costs here can be significantly higher.
A cheap cell phone service can be >$50 a month. No land line needed.
Water and electricty should never exceed 100 a month.
Cars are expensive. Assuming no maintenance its still registration, insurance and gas. In california a car is practically a necessity though so factor in another 200 (but realistically $400) a month.
So for $1.3k or so you can afford to live on your own working full time minimum wage. As far as living goes it might be cheaper to have a roommate if you split the cost 50/50. I half wonder if I should do this myself and spend my freetime programming as spending money income/skill building. Because comp sci degrees are vastly becoming a joke for the most part among software companies looking for new developers. I feel more and more that the college path is a waste of time and money when I work for a software company as QA atm and most of the developers werent college grads they were people interested in learning programming.
Depends on where you live, Here I can live for <$1000/month and with that can still afford paying $85 for my internet and $70 for my cell. I do not have the Tv or a landline phone though. I live in a small Canadian province so my 1 room and still pretty big appartment costs me $490 a month and that's in a good neighborhood of a small city. $80 doesn't go far for groceries here though, Even just getting the nececities (such as bread (that I always get on half price sales), milk and some other basic foods, and not brand names either) comes to around $30 a week, and that's when I go between the 3 grocery stores (they're all near each other so it's not a problem) to get the best prices and sales. I do have a car, but being a fully paid car and a Toyota Echo, it doesn't cost me much either compared to other people. It costs me on average $110/month to have that car. About $60 for insurance and $50 for gas for the full month although sometimes it can cost more depending on the gas prices.
I also thing your "cheap" >$50 cell plan can be even lower than that if you don't have a smartphone. Before getting my Android phone last year, my cell bill was $38/month.